From 57e734423adda83f3b05505875343284efe3b39c Mon Sep 17 00:00:00 2001 From: "Tobin C. Harding" Date: Thu, 23 Nov 2017 10:56:39 +1100 Subject: vsprintf: refactor %pK code out of pointer() Currently code to handle %pK is all within the switch statement in pointer(). This is the wrong level of abstraction. Each of the other switch clauses call a helper function, pK should do the same. Refactor code out of pointer() to new function restricted_pointer(). Signed-off-by: Tobin C. Harding --- lib/vsprintf.c | 97 ++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 54 insertions(+), 43 deletions(-) (limited to 'lib') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 1746bae94d41..8dc5cf85cef4 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1343,6 +1343,59 @@ char *uuid_string(char *buf, char *end, const u8 *addr, return string(buf, end, uuid, spec); } +int kptr_restrict __read_mostly; + +static noinline_for_stack +char *restricted_pointer(char *buf, char *end, const void *ptr, + struct printf_spec spec) +{ + spec.base = 16; + spec.flags |= SMALL; + if (spec.field_width == -1) { + spec.field_width = 2 * sizeof(ptr); + spec.flags |= ZEROPAD; + } + + switch (kptr_restrict) { + case 0: + /* Always print %pK values */ + break; + case 1: { + const struct cred *cred; + + /* + * kptr_restrict==1 cannot be used in IRQ context + * because its test for CAP_SYSLOG would be meaningless. + */ + if (in_irq() || in_serving_softirq() || in_nmi()) + return string(buf, end, "pK-error", spec); + + /* + * Only print the real pointer value if the current + * process has CAP_SYSLOG and is running with the + * same credentials it started with. This is because + * access to files is checked at open() time, but %pK + * checks permission at read() time. We don't want to + * leak pointer values if a binary opens a file using + * %pK and then elevates privileges before reading it. + */ + cred = current_cred(); + if (!has_capability_noaudit(current, CAP_SYSLOG) || + !uid_eq(cred->euid, cred->uid) || + !gid_eq(cred->egid, cred->gid)) + ptr = NULL; + break; + } + case 2: + default: + /* Always print 0's for %pK */ + ptr = NULL; + break; + } + + return number(buf, end, (unsigned long)ptr, spec); +} + static noinline_for_stack char *netdev_bits(char *buf, char *end, const void *addr, const char *fmt) { @@ -1591,8 +1644,6 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, return widen_string(buf, buf - buf_start, end, spec); } -int kptr_restrict __read_mostly; - /* * Show a '%p' thing. A kernel extension is that the '%p' is followed * by an extra set of alphanumeric characters that are extended format @@ -1792,47 +1843,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, return buf; } case 'K': - switch (kptr_restrict) { - case 0: - /* Always print %pK values */ - break; - case 1: { - const struct cred *cred; - - /* - * kptr_restrict==1 cannot be used in IRQ context - * because its test for CAP_SYSLOG would be meaningless. - */ - if (in_irq() || in_serving_softirq() || in_nmi()) { - if (spec.field_width == -1) - spec.field_width = default_width; - return string(buf, end, "pK-error", spec); - } - - /* - * Only print the real pointer value if the current - * process has CAP_SYSLOG and is running with the - * same credentials it started with. This is because - * access to files is checked at open() time, but %pK - * checks permission at read() time. We don't want to - * leak pointer values if a binary opens a file using - * %pK and then elevates privileges before reading it. - */ - cred = current_cred(); - if (!has_capability_noaudit(current, CAP_SYSLOG) || - !uid_eq(cred->euid, cred->uid) || - !gid_eq(cred->egid, cred->gid)) - ptr = NULL; - break; - } - case 2: - default: - /* Always print 0's for %pK */ - ptr = NULL; - break; - } - break; - + return restricted_pointer(buf, end, ptr, spec); case 'N': return netdev_bits(buf, end, ptr, fmt); case 'a': -- cgit From ad67b74d2469d9b82aaa572d76474c95bc484d57 Mon Sep 17 00:00:00 2001 From: "Tobin C. Harding" Date: Wed, 1 Nov 2017 15:32:23 +1100 Subject: printk: hash addresses printed with %p Currently there exist approximately 14 000 places in the kernel where addresses are being printed using an unadorned %p. This potentially leaks sensitive information regarding the Kernel layout in memory. Many of these calls are stale, instead of fixing every call lets hash the address by default before printing. This will of course break some users, forcing code printing needed addresses to be updated. Code that _really_ needs the address will soon be able to use the new printk specifier %px to print the address. For what it's worth, usage of unadorned %p can be broken down as follows (thanks to Joe Perches). $ git grep -E '%p[^A-Za-z0-9]' | cut -f1 -d"/" | sort | uniq -c 1084 arch 20 block 10 crypto 32 Documentation 8121 drivers 1221 fs 143 include 101 kernel 69 lib 100 mm 1510 net 40 samples 7 scripts 11 security 166 sound 152 tools 2 virt Add function ptr_to_id() to map an address to a 32 bit unique identifier. Hash any unadorned usage of specifier %p and any malformed specifiers. Signed-off-by: Tobin C. Harding --- lib/test_printf.c | 108 +++++++++++++++++++++++++++++++++++------------------- lib/vsprintf.c | 81 ++++++++++++++++++++++++++++++++++++---- 2 files changed, 144 insertions(+), 45 deletions(-) (limited to 'lib') diff --git a/lib/test_printf.c b/lib/test_printf.c index 563f10e6876a..71ebfa43ad05 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -24,24 +24,6 @@ #define PAD_SIZE 16 #define FILL_CHAR '$' -#define PTR1 ((void*)0x01234567) -#define PTR2 ((void*)(long)(int)0xfedcba98) - -#if BITS_PER_LONG == 64 -#define PTR1_ZEROES "000000000" -#define PTR1_SPACES " " -#define PTR1_STR "1234567" -#define PTR2_STR "fffffffffedcba98" -#define PTR_WIDTH 16 -#else -#define PTR1_ZEROES "0" -#define PTR1_SPACES " " -#define PTR1_STR "1234567" -#define PTR2_STR "fedcba98" -#define PTR_WIDTH 8 -#endif -#define PTR_WIDTH_STR stringify(PTR_WIDTH) - static unsigned total_tests __initdata; static unsigned failed_tests __initdata; static char *test_buffer __initdata; @@ -217,30 +199,79 @@ test_string(void) test("a | | ", "%-3.s|%-3.0s|%-3.*s", "a", "b", 0, "c"); } +#define PLAIN_BUF_SIZE 64 /* leave some space so we don't oops */ + +#if BITS_PER_LONG == 64 + +#define PTR_WIDTH 16 +#define PTR ((void *)0xffff0123456789ab) +#define PTR_STR "ffff0123456789ab" +#define ZEROS "00000000" /* hex 32 zero bits */ + +static int __init +plain_format(void) +{ + char buf[PLAIN_BUF_SIZE]; + int nchars; + + nchars = snprintf(buf, PLAIN_BUF_SIZE, "%p", PTR); + + if (nchars != PTR_WIDTH || strncmp(buf, ZEROS, strlen(ZEROS)) != 0) + return -1; + + return 0; +} + +#else + +#define PTR_WIDTH 8 +#define PTR ((void *)0x456789ab) +#define PTR_STR "456789ab" + +static int __init +plain_format(void) +{ + /* Format is implicitly tested for 32 bit machines by plain_hash() */ + return 0; +} + +#endif /* BITS_PER_LONG == 64 */ + +static int __init +plain_hash(void) +{ + char buf[PLAIN_BUF_SIZE]; + int nchars; + + nchars = snprintf(buf, PLAIN_BUF_SIZE, "%p", PTR); + + if (nchars != PTR_WIDTH || strncmp(buf, PTR_STR, PTR_WIDTH) == 0) + return -1; + + return 0; +} + +/* + * We can't use test() to test %p because we don't know what output to expect + * after an address is hashed. + */ static void __init plain(void) { - test(PTR1_ZEROES PTR1_STR " " PTR2_STR, "%p %p", PTR1, PTR2); - /* - * The field width is overloaded for some %p extensions to - * pass another piece of information. For plain pointers, the - * behaviour is slightly odd: One cannot pass either the 0 - * flag nor a precision to %p without gcc complaining, and if - * one explicitly gives a field width, the number is no longer - * zero-padded. - */ - test("|" PTR1_STR PTR1_SPACES " | " PTR1_SPACES PTR1_STR "|", - "|%-*p|%*p|", PTR_WIDTH+2, PTR1, PTR_WIDTH+2, PTR1); - test("|" PTR2_STR " | " PTR2_STR "|", - "|%-*p|%*p|", PTR_WIDTH+2, PTR2, PTR_WIDTH+2, PTR2); + int err; - /* - * Unrecognized %p extensions are treated as plain %p, but the - * alphanumeric suffix is ignored (that is, does not occur in - * the output.) - */ - test("|"PTR1_ZEROES PTR1_STR"|", "|%p0y|", PTR1); - test("|"PTR2_STR"|", "|%p0y|", PTR2); + err = plain_hash(); + if (err) { + pr_warn("plain 'p' does not appear to be hashed\n"); + failed_tests++; + return; + } + + err = plain_format(); + if (err) { + pr_warn("hashing plain 'p' has unexpected format\n"); + failed_tests++; + } } static void __init @@ -251,6 +282,7 @@ symbol_ptr(void) static void __init kernel_ptr(void) { + /* We can't test this without access to kptr_restrict. */ } static void __init diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 8dc5cf85cef4..d69452a0f2fa 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -33,6 +33,8 @@ #include #include #include +#include +#include #ifdef CONFIG_BLOCK #include #endif @@ -1644,6 +1646,73 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, return widen_string(buf, buf - buf_start, end, spec); } +static bool have_filled_random_ptr_key __read_mostly; +static siphash_key_t ptr_key __read_mostly; + +static void fill_random_ptr_key(struct random_ready_callback *unused) +{ + get_random_bytes(&ptr_key, sizeof(ptr_key)); + /* + * have_filled_random_ptr_key==true is dependent on get_random_bytes(). + * ptr_to_id() needs to see have_filled_random_ptr_key==true + * after get_random_bytes() returns. + */ + smp_mb(); + WRITE_ONCE(have_filled_random_ptr_key, true); +} + +static struct random_ready_callback random_ready = { + .func = fill_random_ptr_key +}; + +static int __init initialize_ptr_random(void) +{ + int ret = add_random_ready_callback(&random_ready); + + if (!ret) { + return 0; + } else if (ret == -EALREADY) { + fill_random_ptr_key(&random_ready); + return 0; + } + + return ret; +} +early_initcall(initialize_ptr_random); + +/* Maps a pointer to a 32 bit unique identifier. */ +static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec) +{ + unsigned long hashval; + const int default_width = 2 * sizeof(ptr); + + if (unlikely(!have_filled_random_ptr_key)) { + spec.field_width = default_width; + /* string length must be less than default_width */ + return string(buf, end, "(ptrval)", spec); + } + +#ifdef CONFIG_64BIT + hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key); + /* + * Mask off the first 32 bits, this makes explicit that we have + * modified the address (and 32 bits is plenty for a unique ID). + */ + hashval = hashval & 0xffffffff; +#else + hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key); +#endif + + spec.flags |= SMALL; + if (spec.field_width == -1) { + spec.field_width = default_width; + spec.flags |= ZEROPAD; + } + spec.base = 16; + + return number(buf, end, hashval, spec); +} + /* * Show a '%p' thing. A kernel extension is that the '%p' is followed * by an extra set of alphanumeric characters that are extended format @@ -1754,6 +1823,9 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, * Note: The difference between 'S' and 'F' is that on ia64 and ppc64 * function pointers are really function descriptors, which contain a * pointer to the real address. + * + * Note: The default behaviour (unadorned %p) is to hash the address, + * rendering it useful as a unique identifier. */ static noinline_for_stack char *pointer(const char *fmt, char *buf, char *end, void *ptr, @@ -1869,14 +1941,9 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, return device_node_string(buf, end, ptr, spec, fmt + 1); } } - spec.flags |= SMALL; - if (spec.field_width == -1) { - spec.field_width = default_width; - spec.flags |= ZEROPAD; - } - spec.base = 16; - return number(buf, end, (unsigned long) ptr, spec); + /* default is to _not_ leak addresses, hash before printing */ + return ptr_to_id(buf, end, ptr, spec); } /* -- cgit From 7b1924a1d930eb27fc79c4e4e2a6c1c970623e68 Mon Sep 17 00:00:00 2001 From: "Tobin C. Harding" Date: Thu, 23 Nov 2017 10:59:45 +1100 Subject: vsprintf: add printk specifier %px printk specifier %p now hashes all addresses before printing. Sometimes we need to see the actual unmodified address. This can be achieved using %lx but then we face the risk that if in future we want to change the way the Kernel handles printing of pointers we will have to grep through the already existent 50 000 %lx call sites. Let's add specifier %px as a clear, opt-in, way to print a pointer and maintain some level of isolation from all the other hex integer output within the Kernel. Add printk specifier %px to print the actual unmodified address. Signed-off-by: Tobin C. Harding --- lib/vsprintf.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'lib') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index d69452a0f2fa..d960aead0336 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1646,6 +1646,20 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, return widen_string(buf, buf - buf_start, end, spec); } +static noinline_for_stack +char *pointer_string(char *buf, char *end, const void *ptr, + struct printf_spec spec) +{ + spec.base = 16; + spec.flags |= SMALL; + if (spec.field_width == -1) { + spec.field_width = 2 * sizeof(ptr); + spec.flags |= ZEROPAD; + } + + return number(buf, end, (unsigned long int)ptr, spec); +} + static bool have_filled_random_ptr_key __read_mostly; static siphash_key_t ptr_key __read_mostly; @@ -1818,6 +1832,8 @@ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec) * c major compatible string * C full compatible string * + * - 'x' For printing the address. Equivalent to "%lx". + * * ** Please update also Documentation/printk-formats.txt when making changes ** * * Note: The difference between 'S' and 'F' is that on ia64 and ppc64 @@ -1940,6 +1956,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'F': return device_node_string(buf, end, ptr, spec, fmt + 1); } + case 'x': + return pointer_string(buf, end, ptr, spec); } /* default is to _not_ leak addresses, hash before printing */ -- cgit From ef0010a30935de4e0211cbc7bdffc30446cdee9b Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 29 Nov 2017 11:28:09 -0800 Subject: vsprintf: don't use 'restricted_pointer()' when not restricting Instead, just fall back on the new '%p' behavior which hashes the pointer. Otherwise, '%pK' - that was intended to mark a pointer as restricted - just ends up leaking pointers that a normal '%p' wouldn't leak. Which just make the whole thing pointless. I suspect we should actually get rid of '%pK' entirely, and make it just work as '%p' regardless, but this is the minimal obvious fix. People who actually use 'kptr_restrict' should weigh in on which behavior they want. Cc: Tobin Harding Cc: Kees Cook Signed-off-by: Linus Torvalds --- lib/vsprintf.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'lib') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index d960aead0336..01c3957b2de6 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1931,6 +1931,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, return buf; } case 'K': + if (!kptr_restrict) + break; return restricted_pointer(buf, end, ptr, spec); case 'N': return netdev_bits(buf, end, ptr, fmt); -- cgit From 4db2b604c05afc3d2678fe01d3136c015df313ec Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 22 Nov 2017 11:47:28 +0100 Subject: move libgcc.h to include/linux Introducing a new include/lib directory just for this file totally messes up tab completion for include/linux, which is highly annoying. Move it to include/linux where we have headers for all kinds of other lib/ code as well. Signed-off-by: Christoph Hellwig Signed-off-by: Palmer Dabbelt --- lib/ashldi3.c | 2 +- lib/ashrdi3.c | 2 +- lib/cmpdi2.c | 2 +- lib/lshrdi3.c | 2 +- lib/muldi3.c | 2 +- lib/ucmpdi2.c | 2 +- 6 files changed, 6 insertions(+), 6 deletions(-) (limited to 'lib') diff --git a/lib/ashldi3.c b/lib/ashldi3.c index 1b6087db95a5..3ffc46e3bb6c 100644 --- a/lib/ashldi3.c +++ b/lib/ashldi3.c @@ -16,7 +16,7 @@ #include -#include +#include long long notrace __ashldi3(long long u, word_type b) { diff --git a/lib/ashrdi3.c b/lib/ashrdi3.c index 2e67c97ac65a..ea054550f0e8 100644 --- a/lib/ashrdi3.c +++ b/lib/ashrdi3.c @@ -16,7 +16,7 @@ #include -#include +#include long long notrace __ashrdi3(long long u, word_type b) { diff --git a/lib/cmpdi2.c b/lib/cmpdi2.c index 6d7ebf6c2b86..2250da7e503e 100644 --- a/lib/cmpdi2.c +++ b/lib/cmpdi2.c @@ -16,7 +16,7 @@ #include -#include +#include word_type notrace __cmpdi2(long long a, long long b) { diff --git a/lib/lshrdi3.c b/lib/lshrdi3.c index 8e845f4bb65f..99cfa5721f2d 100644 --- a/lib/lshrdi3.c +++ b/lib/lshrdi3.c @@ -17,7 +17,7 @@ */ #include -#include +#include long long notrace __lshrdi3(long long u, word_type b) { diff --git a/lib/muldi3.c b/lib/muldi3.c index 88938543e10a..54c8b3123376 100644 --- a/lib/muldi3.c +++ b/lib/muldi3.c @@ -15,7 +15,7 @@ */ #include -#include +#include #define W_TYPE_SIZE 32 diff --git a/lib/ucmpdi2.c b/lib/ucmpdi2.c index 49a53505c8e3..25ca2d4c1e19 100644 --- a/lib/ucmpdi2.c +++ b/lib/ucmpdi2.c @@ -15,7 +15,7 @@ */ #include -#include +#include word_type __ucmpdi2(unsigned long long a, unsigned long long b) { -- cgit From 6e237d099fac1f73a7b6d7287bb9191f29585a4e Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 6 Dec 2017 20:09:12 -0800 Subject: netlink: Relax attr validation for fixed length types Commit 28033ae4e0f5 ("net: netlink: Update attr validation to require exact length for some types") requires attributes using types NLA_U* and NLA_S* to have an exact length. This change is exposing bugs in various userspace commands that are sending attributes with an invalid length (e.g., attribute has type NLA_U8 and userspace sends NLA_U32). While the commands are clearly broken and need to be fixed, users are arguing that the sudden change in enforcement is breaking older commands on newer kernels for use cases that otherwise "worked". Relax the validation to print a warning mesage similar to what is done for messages containing extra bytes after parsing. Fixes: 28033ae4e0f5 ("net: netlink: Update attr validation to require exact length for some types") Signed-off-by: David Ahern Reviewed-by: Johannes Berg Signed-off-by: David S. Miller --- lib/nlattr.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) (limited to 'lib') diff --git a/lib/nlattr.c b/lib/nlattr.c index 8bf78b4b78f0..dfa55c873c13 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -15,7 +15,11 @@ #include #include -/* for these data types attribute length must be exactly given size */ +/* For these data types, attribute length should be exactly the given + * size. However, to maintain compatibility with broken commands, if the + * attribute length does not match the expected size a warning is emitted + * to the user that the command is sending invalid data and needs to be fixed. + */ static const u8 nla_attr_len[NLA_TYPE_MAX+1] = { [NLA_U8] = sizeof(u8), [NLA_U16] = sizeof(u16), @@ -28,8 +32,16 @@ static const u8 nla_attr_len[NLA_TYPE_MAX+1] = { }; static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = { + [NLA_U8] = sizeof(u8), + [NLA_U16] = sizeof(u16), + [NLA_U32] = sizeof(u32), + [NLA_U64] = sizeof(u64), [NLA_MSECS] = sizeof(u64), [NLA_NESTED] = NLA_HDRLEN, + [NLA_S8] = sizeof(s8), + [NLA_S16] = sizeof(s16), + [NLA_S32] = sizeof(s32), + [NLA_S64] = sizeof(s64), }; static int validate_nla_bitfield32(const struct nlattr *nla, @@ -69,11 +81,9 @@ static int validate_nla(const struct nlattr *nla, int maxtype, BUG_ON(pt->type > NLA_TYPE_MAX); - /* for data types NLA_U* and NLA_S* require exact length */ - if (nla_attr_len[pt->type]) { - if (attrlen != nla_attr_len[pt->type]) - return -ERANGE; - return 0; + if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) { + pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", + current->comm, type); } switch (pt->type) { -- cgit From e0058f3a874ebb48b25be7ff79bc3b4e59929f90 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 8 Dec 2017 15:13:27 +0000 Subject: ASN.1: fix out-of-bounds read when parsing indefinite length item In asn1_ber_decoder(), indefinitely-sized ASN.1 items were being passed to the action functions before their lengths had been computed, using the bogus length of 0x80 (ASN1_INDEFINITE_LENGTH). This resulted in reading data past the end of the input buffer, when given a specially crafted message. Fix it by rearranging the code so that the indefinite length is resolved before the action is called. This bug was originally found by fuzzing the X.509 parser in userspace using libFuzzer from the LLVM project. KASAN report (cleaned up slightly): BUG: KASAN: slab-out-of-bounds in memcpy ./include/linux/string.h:341 [inline] BUG: KASAN: slab-out-of-bounds in x509_fabricate_name.constprop.1+0x1a4/0x940 crypto/asymmetric_keys/x509_cert_parser.c:366 Read of size 128 at addr ffff880035dd9eaf by task keyctl/195 CPU: 1 PID: 195 Comm: keyctl Not tainted 4.14.0-09238-g1d3b78bbc6e9 #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-20171110_100015-anatol 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xd1/0x175 lib/dump_stack.c:53 print_address_description+0x78/0x260 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x23f/0x350 mm/kasan/report.c:409 memcpy+0x1f/0x50 mm/kasan/kasan.c:302 memcpy ./include/linux/string.h:341 [inline] x509_fabricate_name.constprop.1+0x1a4/0x940 crypto/asymmetric_keys/x509_cert_parser.c:366 asn1_ber_decoder+0xb4a/0x1fd0 lib/asn1_decoder.c:447 x509_cert_parse+0x1c7/0x620 crypto/asymmetric_keys/x509_cert_parser.c:89 x509_key_preparse+0x61/0x750 crypto/asymmetric_keys/x509_public_key.c:174 asymmetric_key_preparse+0xa4/0x150 crypto/asymmetric_keys/asymmetric_type.c:388 key_create_or_update+0x4d4/0x10a0 security/keys/key.c:850 SYSC_add_key security/keys/keyctl.c:122 [inline] SyS_add_key+0xe8/0x290 security/keys/keyctl.c:62 entry_SYSCALL_64_fastpath+0x1f/0x96 Allocated by task 195: __do_kmalloc_node mm/slab.c:3675 [inline] __kmalloc_node+0x47/0x60 mm/slab.c:3682 kvmalloc ./include/linux/mm.h:540 [inline] SYSC_add_key security/keys/keyctl.c:104 [inline] SyS_add_key+0x19e/0x290 security/keys/keyctl.c:62 entry_SYSCALL_64_fastpath+0x1f/0x96 Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Reported-by: Alexander Potapenko Cc: # v3.7+ Signed-off-by: Eric Biggers Signed-off-by: David Howells --- lib/asn1_decoder.c | 47 ++++++++++++++++++++++++++--------------------- 1 file changed, 26 insertions(+), 21 deletions(-) (limited to 'lib') diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c index 1ef0cec38d78..d77cdfc4b554 100644 --- a/lib/asn1_decoder.c +++ b/lib/asn1_decoder.c @@ -313,42 +313,47 @@ next_op: /* Decide how to handle the operation */ switch (op) { - case ASN1_OP_MATCH_ANY_ACT: - case ASN1_OP_MATCH_ANY_ACT_OR_SKIP: - case ASN1_OP_COND_MATCH_ANY_ACT: - case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP: - ret = actions[machine[pc + 1]](context, hdr, tag, data + dp, len); - if (ret < 0) - return ret; - goto skip_data; - - case ASN1_OP_MATCH_ACT: - case ASN1_OP_MATCH_ACT_OR_SKIP: - case ASN1_OP_COND_MATCH_ACT_OR_SKIP: - ret = actions[machine[pc + 2]](context, hdr, tag, data + dp, len); - if (ret < 0) - return ret; - goto skip_data; - case ASN1_OP_MATCH: case ASN1_OP_MATCH_OR_SKIP: + case ASN1_OP_MATCH_ACT: + case ASN1_OP_MATCH_ACT_OR_SKIP: case ASN1_OP_MATCH_ANY: case ASN1_OP_MATCH_ANY_OR_SKIP: + case ASN1_OP_MATCH_ANY_ACT: + case ASN1_OP_MATCH_ANY_ACT_OR_SKIP: case ASN1_OP_COND_MATCH_OR_SKIP: + case ASN1_OP_COND_MATCH_ACT_OR_SKIP: case ASN1_OP_COND_MATCH_ANY: case ASN1_OP_COND_MATCH_ANY_OR_SKIP: - skip_data: + case ASN1_OP_COND_MATCH_ANY_ACT: + case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP: + if (!(flags & FLAG_CONS)) { if (flags & FLAG_INDEFINITE_LENGTH) { + size_t tmp = dp; + ret = asn1_find_indefinite_length( - data, datalen, &dp, &len, &errmsg); + data, datalen, &tmp, &len, &errmsg); if (ret < 0) goto error; - } else { - dp += len; } pr_debug("- LEAF: %zu\n", len); } + + if (op & ASN1_OP_MATCH__ACT) { + unsigned char act; + + if (op & ASN1_OP_MATCH__ANY) + act = machine[pc + 1]; + else + act = machine[pc + 2]; + ret = actions[act](context, hdr, tag, data + dp, len); + if (ret < 0) + return ret; + } + + if (!(flags & FLAG_CONS)) + dp += len; pc += asn1_op_lengths[op]; goto next_op; -- cgit From 81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 8 Dec 2017 15:13:27 +0000 Subject: ASN.1: check for error from ASN1_OP_END__ACT actions asn1_ber_decoder() was ignoring errors from actions associated with the opcodes ASN1_OP_END_SEQ_ACT, ASN1_OP_END_SET_ACT, ASN1_OP_END_SEQ_OF_ACT, and ASN1_OP_END_SET_OF_ACT. In practice, this meant the pkcs7_note_signed_info() action (since that was the only user of those opcodes). Fix it by checking for the error, just like the decoder does for actions associated with the other opcodes. This bug allowed users to leak slab memory by repeatedly trying to add a specially crafted "pkcs7_test" key (requires CONFIG_PKCS7_TEST_KEY). In theory, this bug could also be used to bypass module signature verification, by providing a PKCS#7 message that is misparsed such that a signature's ->authattrs do not contain its ->msgdigest. But it doesn't seem practical in normal cases, due to restrictions on the format of the ->authattrs. Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Cc: # v3.7+ Signed-off-by: Eric Biggers Signed-off-by: David Howells Reviewed-by: James Morris --- lib/asn1_decoder.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'lib') diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c index d77cdfc4b554..dc14beae2c9a 100644 --- a/lib/asn1_decoder.c +++ b/lib/asn1_decoder.c @@ -439,6 +439,8 @@ next_op: else act = machine[pc + 1]; ret = actions[act](context, hdr, 0, data + tdp, len); + if (ret < 0) + return ret; } pc += asn1_op_lengths[op]; goto next_op; -- cgit From 47e0a208fb9d91e3f3c86309e752b13a36470ae8 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 8 Dec 2017 15:13:28 +0000 Subject: X.509: fix buffer overflow detection in sprint_oid() In sprint_oid(), if the input buffer were to be more than 1 byte too small for the first snprintf(), 'bufsize' would underflow, causing a buffer overflow when printing the remainder of the OID. Fortunately this cannot actually happen currently, because no users pass in a buffer that can be too small for the first snprintf(). Regardless, fix it by checking the snprintf() return value correctly. For consistency also tweak the second snprintf() check to look the same. Fixes: 4f73175d0375 ("X.509: Add utility functions to render OIDs as strings") Cc: Takashi Iwai Signed-off-by: Eric Biggers Signed-off-by: David Howells Reviewed-by: James Morris --- lib/oid_registry.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'lib') diff --git a/lib/oid_registry.c b/lib/oid_registry.c index 41b9e50711a7..5a75d127995d 100644 --- a/lib/oid_registry.c +++ b/lib/oid_registry.c @@ -120,10 +120,10 @@ int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) n = *v++; ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40); + if (count >= bufsize) + return -ENOBUFS; buffer += count; bufsize -= count; - if (bufsize == 0) - return -ENOBUFS; while (v < end) { num = 0; @@ -141,9 +141,9 @@ int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) } while (n & 0x80); } ret += count = snprintf(buffer, bufsize, ".%lu", num); - buffer += count; - if (bufsize <= count) + if (count >= bufsize) return -ENOBUFS; + buffer += count; bufsize -= count; } -- cgit From 8dfd2f22d3bf3ab7714f7495ad5d897b8845e8c1 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 8 Dec 2017 15:13:28 +0000 Subject: 509: fix printing uninitialized stack memory when OID is empty Callers of sprint_oid() do not check its return value before printing the result. In the case where the OID is zero-length, -EBADMSG was being returned without anything being written to the buffer, resulting in uninitialized stack memory being printed. Fix this by writing "(bad)" to the buffer in the cases where -EBADMSG is returned. Fixes: 4f73175d0375 ("X.509: Add utility functions to render OIDs as strings") Signed-off-by: Eric Biggers Signed-off-by: David Howells --- lib/oid_registry.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/oid_registry.c b/lib/oid_registry.c index 5a75d127995d..0bcac6ccb1b2 100644 --- a/lib/oid_registry.c +++ b/lib/oid_registry.c @@ -116,7 +116,7 @@ int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) int count; if (v >= end) - return -EBADMSG; + goto bad; n = *v++; ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40); @@ -134,7 +134,7 @@ int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) num = n & 0x7f; do { if (v >= end) - return -EBADMSG; + goto bad; n = *v++; num <<= 7; num |= n & 0x7f; @@ -148,6 +148,10 @@ int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) } return ret; + +bad: + snprintf(buffer, bufsize, "(bad)"); + return -EBADMSG; } EXPORT_SYMBOL_GPL(sprint_oid); -- cgit From bbc25bee37d2b32cf3a1fab9195b6da3a185614a Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 5 Dec 2017 23:31:35 +0000 Subject: lib/mpi: Fix umul_ppmm() for MIPS64r6 Current MIPS64r6 toolchains aren't able to generate efficient DMULU/DMUHU based code for the C implementation of umul_ppmm(), which performs an unsigned 64 x 64 bit multiply and returns the upper and lower 64-bit halves of the 128-bit result. Instead it widens the 64-bit inputs to 128-bits and emits a __multi3 intrinsic call to perform a 128 x 128 multiply. This is both inefficient, and it results in a link error since we don't include __multi3 in MIPS linux. For example commit 90a53e4432b1 ("cfg80211: implement regdb signature checking") merged in v4.15-rc1 recently broke the 64r6_defconfig and 64r6el_defconfig builds by indirectly selecting MPILIB. The same build errors can be reproduced on older kernels by enabling e.g. CRYPTO_RSA: lib/mpi/generic_mpih-mul1.o: In function `mpihelp_mul_1': lib/mpi/generic_mpih-mul1.c:50: undefined reference to `__multi3' lib/mpi/generic_mpih-mul2.o: In function `mpihelp_addmul_1': lib/mpi/generic_mpih-mul2.c:49: undefined reference to `__multi3' lib/mpi/generic_mpih-mul3.o: In function `mpihelp_submul_1': lib/mpi/generic_mpih-mul3.c:49: undefined reference to `__multi3' lib/mpi/mpih-div.o In function `mpihelp_divrem': lib/mpi/mpih-div.c:205: undefined reference to `__multi3' lib/mpi/mpih-div.c:142: undefined reference to `__multi3' Therefore add an efficient MIPS64r6 implementation of umul_ppmm() using inline assembly and the DMULU/DMUHU instructions, to prevent __multi3 calls being emitted. Fixes: 7fd08ca58ae6 ("MIPS: Add build support for the MIPS R6 ISA") Signed-off-by: James Hogan Cc: Ralf Baechle Cc: Herbert Xu Cc: "David S. Miller" Cc: linux-mips@linux-mips.org Cc: linux-crypto@vger.kernel.org Signed-off-by: Herbert Xu --- lib/mpi/longlong.h | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h index 57fd45ab7af1..08c60d10747f 100644 --- a/lib/mpi/longlong.h +++ b/lib/mpi/longlong.h @@ -671,7 +671,23 @@ do { \ ************** MIPS/64 ************** ***************************************/ #if (defined(__mips) && __mips >= 3) && W_TYPE_SIZE == 64 -#if (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4) +#if defined(__mips_isa_rev) && __mips_isa_rev >= 6 +/* + * GCC ends up emitting a __multi3 intrinsic call for MIPS64r6 with the plain C + * code below, so we special case MIPS64r6 until the compiler can do better. + */ +#define umul_ppmm(w1, w0, u, v) \ +do { \ + __asm__ ("dmulu %0,%1,%2" \ + : "=d" ((UDItype)(w0)) \ + : "d" ((UDItype)(u)), \ + "d" ((UDItype)(v))); \ + __asm__ ("dmuhu %0,%1,%2" \ + : "=d" ((UDItype)(w1)) \ + : "d" ((UDItype)(u)), \ + "d" ((UDItype)(v))); \ +} while (0) +#elif (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4) #define umul_ppmm(w1, w0, u, v) \ do { \ typedef unsigned int __ll_UTItype __attribute__((mode(TI))); \ -- cgit