4.19-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
commit 3af349639597fea582a93604734d717e59a0e223 upstream.
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: stable@vger.kernel.org # v4.17+ Cc: Dave Watson davejwatson@fb.com Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/crypto/aesni-intel_glue.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
--- a/arch/x86/crypto/aesni-intel_glue.c +++ b/arch/x86/crypto/aesni-intel_glue.c @@ -830,11 +830,14 @@ static int gcmaes_crypt_by_sg(bool enc, 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();