[PATCH v2 05/15] crypto: x86/aesni-gcm - fix crash on empty plaintext
From: Eric Biggers <ebiggers@kernel.org>
Date: 2019-02-01 07:52:17
Also in:
lkml, stable
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Eric Biggers <redacted>
gcmaes_crypt_by_sg() dereferences the NULL pointer returned by
scatterwalk_ffwd() when encrypting an empty plaintext and the source
scatterlist ends immediately after the associated data.
Fix it by only fast-forwarding to the src/dst data scatterlists if the
data length is nonzero.
This bug is reproduced by the "rfc4543(gcm(aes))" test vectors when run
with the new AEAD test manager.
Fixes: e845520707f8 ("crypto: aesni - Update aesni-intel_glue to use scatter/gather")
Cc: <redacted> # v4.17+
Cc: Dave Watson <redacted>
Signed-off-by: Eric Biggers <redacted>
---
arch/x86/crypto/aesni-intel_glue.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 9b5ccde3ef315..1e3d2102033a0 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c@@ -813,11 +813,14 @@ static int gcmaes_crypt_by_sg(bool enc, struct aead_request *req, scatterwalk_map_and_copy(assoc, req->src, 0, assoclen, 0); } - src_sg = scatterwalk_ffwd(src_start, req->src, req->assoclen); - scatterwalk_start(&src_sg_walk, src_sg); - if (req->src != req->dst) { - dst_sg = scatterwalk_ffwd(dst_start, req->dst, req->assoclen); - scatterwalk_start(&dst_sg_walk, dst_sg); + if (left) { + src_sg = scatterwalk_ffwd(src_start, req->src, req->assoclen); + scatterwalk_start(&src_sg_walk, src_sg); + if (req->src != req->dst) { + dst_sg = scatterwalk_ffwd(dst_start, req->dst, + req->assoclen); + scatterwalk_start(&dst_sg_walk, dst_sg); + } } kernel_fpu_begin();
--
2.20.1