Messages in this thread | | | Date | Mon, 30 Jan 2023 15:34:42 +0800 | Subject | Re: [PATCH] crypto: arm64/sm4 - Fix possible crash in GCM cryption | From | Tianjia Zhang <> |
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Hi Herbert,
On 1/18/23 10:54 PM, Herbert Xu wrote: > On Wed, Jan 18, 2023 at 10:19:28PM +0800, Tianjia Zhang wrote: >> When the cryption total length is zero, GCM cryption call >> skcipher_walk_done() will cause an unexpected crash, so skip calling >> this function to avoid possible crash when the GCM cryption length >> is equal to zero. >> >> Fixes: ae1b83c7d572 ("crypto: arm64/sm4 - add CE implementation for GCM mode") >> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> >> --- >> arch/arm64/crypto/sm4-ce-gcm-glue.c | 12 +++++++----- >> 1 file changed, 7 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm64/crypto/sm4-ce-gcm-glue.c b/arch/arm64/crypto/sm4-ce-gcm-glue.c >> index c450a2025ca9..9b63bcf9aa85 100644 >> --- a/arch/arm64/crypto/sm4-ce-gcm-glue.c >> +++ b/arch/arm64/crypto/sm4-ce-gcm-glue.c >> @@ -178,11 +178,13 @@ static int gcm_crypt(struct aead_request *req, struct skcipher_walk *walk, >> >> kernel_neon_end(); >> >> - err = skcipher_walk_done(walk, tail); >> - if (err) >> - return err; >> - if (walk->nbytes) >> - kernel_neon_begin(); >> + if (walk->nbytes) { > > Please do > if (!walk->nbytes) > break;
Thanks for the suggestion, a new patch has been sent.
> > As an additional improvement, the tail calculation can be removed > entirely because you already set the chunksize so the walker should > only be feeding you multiples of chunksize except at the end. > > Cheers I printed the walk->nbytes of each iteration of the walker, it is not always multiples of chunksize except at the end when the algorithm test manager is turned on.
For example, during a GCM encryption process, I get data like this:
total = 4014, nbytes = 2078, tail = 14 total = 1950, nbytes = 16, tail = 0 total = 1934, nbytes = 311, tail = 7 total = 1630, nbytes = 16, tail = 0 total = 1614, nbytes = 16, tail = 0 total = 1598, nbytes = 1598, tail = 14
Is my understanding wrong?
Best regards, Tianjia
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