linux/crypto/hmac.c

264 lines
6.5 KiB

crypto: hash - fix incorrect HASH_MAX_DESCSIZE The "hmac(sha3-224-generic)" algorithm has a descsize of 368 bytes, which is greater than HASH_MAX_DESCSIZE (360) which is only enough for sha3-224-generic. The check in shash_prepare_alg() doesn't catch this because the HMAC template doesn't set descsize on the algorithms, but rather sets it on each individual HMAC transform. This causes a stack buffer overflow when SHASH_DESC_ON_STACK() is used with hmac(sha3-224-generic). Fix it by increasing HASH_MAX_DESCSIZE to the real maximum. Also add a sanity check to hmac_init(). This was detected by the improved crypto self-tests in v5.2, by loading the tcrypt module with CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y enabled. I didn't notice this bug when I ran the self-tests by requesting the algorithms via AF_ALG (i.e., not using tcrypt), probably because the stack layout differs in the two cases and that made a difference here. KASAN report: BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:359 [inline] BUG: KASAN: stack-out-of-bounds in shash_default_import+0x52/0x80 crypto/shash.c:223 Write of size 360 at addr ffff8880651defc8 by task insmod/3689 CPU: 2 PID: 3689 Comm: insmod Tainted: G E 5.1.0-10741-g35c99ffa20edd #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x86/0xc5 lib/dump_stack.c:113 print_address_description+0x7f/0x260 mm/kasan/report.c:188 __kasan_report+0x144/0x187 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x137/0x190 mm/kasan/generic.c:191 memcpy+0x37/0x50 mm/kasan/common.c:125 memcpy include/linux/string.h:359 [inline] shash_default_import+0x52/0x80 crypto/shash.c:223 crypto_shash_import include/crypto/hash.h:880 [inline] hmac_import+0x184/0x240 crypto/hmac.c:102 hmac_init+0x96/0xc0 crypto/hmac.c:107 crypto_shash_init include/crypto/hash.h:902 [inline] shash_digest_unaligned+0x9f/0xf0 crypto/shash.c:194 crypto_shash_digest+0xe9/0x1b0 crypto/shash.c:211 generate_random_hash_testvec.constprop.11+0x1ec/0x5b0 crypto/testmgr.c:1331 test_hash_vs_generic_impl+0x3f7/0x5c0 crypto/testmgr.c:1420 __alg_test_hash+0x26d/0x340 crypto/testmgr.c:1502 alg_test_hash+0x22e/0x330 crypto/testmgr.c:1552 alg_test.part.7+0x132/0x610 crypto/testmgr.c:4931 alg_test+0x1f/0x40 crypto/testmgr.c:4952 Fixes: b68a7ec1e9a3 ("crypto: hash - Remove VLA usage") Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com> Cc: <stable@vger.kernel.org> # v4.20+ Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-05-14 16:13:15 -07:00
crypto: hmac - require that the underlying hash algorithm is unkeyed Because the HMAC template didn't check that its underlying hash algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))" through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC being used without having been keyed, resulting in sha3_update() being called without sha3_init(), causing a stack buffer overflow. This is a very old bug, but it seems to have only started causing real problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3) because the innermost hash's state is ->import()ed from a zeroed buffer, and it just so happens that other hash algorithms are fine with that, but SHA-3 is not. However, there could be arch or hardware-dependent hash algorithms also affected; I couldn't test everything. Fix the bug by introducing a function crypto_shash_alg_has_setkey() which tests whether a shash algorithm is keyed. Then update the HMAC template to require that its underlying hash algorithm is unkeyed. Here is a reproducer: #include <linux/if_alg.h> #include <sys/socket.h> int main() { int algfd; struct sockaddr_alg addr = { .salg_type = "hash", .salg_name = "hmac(hmac(sha3-512-generic))", }; char key[4096] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (const struct sockaddr *)&addr, sizeof(addr)); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)); } Here was the KASAN report from syzbot: BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline] BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044 CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 memcpy include/linux/string.h:341 [inline] sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 crypto_shash_update+0xcb/0x220 crypto/shash.c:109 shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 hmac_finup+0x182/0x330 crypto/hmac.c:152 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172 crypto_shash_digest+0xc4/0x120 crypto/shash.c:186 hmac_setkey+0x36a/0x690 crypto/hmac.c:66 crypto_shash_setkey+0xad/0x190 crypto/shash.c:64 shash_async_setkey+0x47/0x60 crypto/shash.c:207 crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200 hash_setkey+0x40/0x90 crypto/algif_hash.c:446 alg_setkey crypto/af_alg.c:221 [inline] alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254 SYSC_setsockopt net/socket.c:1851 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1830 entry_SYSCALL_64_fastpath+0x1f/0x96 Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-28 18:01:38 -08:00
crypto: hmac - require that the underlying hash algorithm is unkeyed Because the HMAC template didn't check that its underlying hash algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))" through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC being used without having been keyed, resulting in sha3_update() being called without sha3_init(), causing a stack buffer overflow. This is a very old bug, but it seems to have only started causing real problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3) because the innermost hash's state is ->import()ed from a zeroed buffer, and it just so happens that other hash algorithms are fine with that, but SHA-3 is not. However, there could be arch or hardware-dependent hash algorithms also affected; I couldn't test everything. Fix the bug by introducing a function crypto_shash_alg_has_setkey() which tests whether a shash algorithm is keyed. Then update the HMAC template to require that its underlying hash algorithm is unkeyed. Here is a reproducer: #include <linux/if_alg.h> #include <sys/socket.h> int main() { int algfd; struct sockaddr_alg addr = { .salg_type = "hash", .salg_name = "hmac(hmac(sha3-512-generic))", }; char key[4096] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (const struct sockaddr *)&addr, sizeof(addr)); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)); } Here was the KASAN report from syzbot: BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline] BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044 CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 memcpy include/linux/string.h:341 [inline] sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 crypto_shash_update+0xcb/0x220 crypto/shash.c:109 shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 hmac_finup+0x182/0x330 crypto/hmac.c:152 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172 crypto_shash_digest+0xc4/0x120 crypto/shash.c:186 hmac_setkey+0x36a/0x690 crypto/hmac.c:66 crypto_shash_setkey+0xad/0x190 crypto/shash.c:64 shash_async_setkey+0x47/0x60 crypto/shash.c:207 crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200 hash_setkey+0x40/0x90 crypto/algif_hash.c:446 alg_setkey crypto/af_alg.c:221 [inline] alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254 SYSC_setsockopt net/socket.c:1851 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1830 entry_SYSCALL_64_fastpath+0x1f/0x96 Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-28 18:01:38 -08:00
crypto: hmac - require that the underlying hash algorithm is unkeyed Because the HMAC template didn't check that its underlying hash algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))" through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC being used without having been keyed, resulting in sha3_update() being called without sha3_init(), causing a stack buffer overflow. This is a very old bug, but it seems to have only started causing real problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3) because the innermost hash's state is ->import()ed from a zeroed buffer, and it just so happens that other hash algorithms are fine with that, but SHA-3 is not. However, there could be arch or hardware-dependent hash algorithms also affected; I couldn't test everything. Fix the bug by introducing a function crypto_shash_alg_has_setkey() which tests whether a shash algorithm is keyed. Then update the HMAC template to require that its underlying hash algorithm is unkeyed. Here is a reproducer: #include <linux/if_alg.h> #include <sys/socket.h> int main() { int algfd; struct sockaddr_alg addr = { .salg_type = "hash", .salg_name = "hmac(hmac(sha3-512-generic))", }; char key[4096] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (const struct sockaddr *)&addr, sizeof(addr)); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)); } Here was the KASAN report from syzbot: BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline] BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044 CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 memcpy include/linux/string.h:341 [inline] sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 crypto_shash_update+0xcb/0x220 crypto/shash.c:109 shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 hmac_finup+0x182/0x330 crypto/hmac.c:152 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172 crypto_shash_digest+0xc4/0x120 crypto/shash.c:186 hmac_setkey+0x36a/0x690 crypto/hmac.c:66 crypto_shash_setkey+0xad/0x190 crypto/shash.c:64 shash_async_setkey+0x47/0x60 crypto/shash.c:207 crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200 hash_setkey+0x40/0x90 crypto/algif_hash.c:446 alg_setkey crypto/af_alg.c:221 [inline] alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254 SYSC_setsockopt net/socket.c:1851 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1830 entry_SYSCALL_64_fastpath+0x1f/0x96 Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-28 18:01:38 -08:00