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| author | Mark Johnston <markj@FreeBSD.org> | 2021-08-30 18:22:20 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2021-09-06 16:29:51 +0000 |
| commit | 9ca533bfb45aa45d95e434d2682d5c5b667fb022 (patch) | |
| tree | 31706b06bc504c642508d9e3fa71be9b43f6b96a /sys | |
| parent | 2ea6ae7cc8146d2c05e266f80f00d35e9dc6dc24 (diff) | |
| download | src-9ca533bfb45aa45d95e434d2682d5c5b667fb022.tar.gz src-9ca533bfb45aa45d95e434d2682d5c5b667fb022.zip | |
aesni: Avoid a potential out-of-bounds load in aes_encrypt_icm()
Given a partial block at the end of a payload, aes_encrypt_icm() would
perform a 16-byte load of the residual into a temporary variable. This
is unsafe in principle since the full block may cross a page boundary.
Fix the problem by copying the residual into a stack buffer first.
Reported by: syzbot+b7e44cde9e2e89f0f6c9@syzkaller.appspotmail.com
Reported by: syzbot+4b5eaf123a99456b5160@syzkaller.appspotmail.com
Reported by: syzbot+70c74c1aa232633355ca@syzkaller.appspotmail.com
Reported by: syzbot+2c663776a52828373d41@syzkaller.appspotmail.com
Reviewed by: cem, jhb
Sponsored by: The FreeBSD Foundation
(cherry picked from commit 564b6aa7fccd98654207447f870b82659b895e7b)
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/crypto/aesni/aesni_wrap.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/sys/crypto/aesni/aesni_wrap.c b/sys/crypto/aesni/aesni_wrap.c index a8a8ae749c77..f3ba09131c1e 100644 --- a/sys/crypto/aesni/aesni_wrap.c +++ b/sys/crypto/aesni/aesni_wrap.c @@ -213,9 +213,10 @@ aesni_encrypt_icm(int rounds, const void *key_schedule, size_t len, __m128i ctr5, ctr6, ctr7, ctr8; __m128i BSWAP_EPI64; __m128i tout[8]; + __m128i block; struct blocks8 *top; const struct blocks8 *blks; - size_t i, cnt; + size_t i, cnt, resid; BSWAP_EPI64 = _mm_set_epi8(8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7); @@ -273,12 +274,19 @@ aesni_encrypt_icm(int rounds, const void *key_schedule, size_t len, to += AES_BLOCK_LEN; } - /* handle remaining partial round */ - if (len % AES_BLOCK_LEN != 0) { + /* + * Handle remaining partial round. Copy the remaining payload onto the + * stack to ensure that the full block can be loaded safely. + */ + resid = len % AES_BLOCK_LEN; + if (resid != 0) { tmp1 = _mm_shuffle_epi8(ctr1, BSWAP_EPI64); tot = aesni_enc(rounds - 1, key_schedule, tmp1); - tot = tot ^ _mm_loadu_si128((const __m128i *)from); - memcpy(to, &tot, len % AES_BLOCK_LEN); + block = _mm_setzero_si128(); + memcpy(&block, from, resid); + tot = tot ^ _mm_loadu_si128(&block); + memcpy(to, &tot, resid); + explicit_bzero(&block, sizeof(block)); } } |