Messages in this thread Patch in this message | | | Date | Tue, 20 Dec 2022 15:24:48 +0800 | From | Herbert Xu <> | Subject | [PATCH] lib/mpi: Fix buffer overrun when SG is too long |
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On Mon, Dec 19, 2022 at 09:49:29AM +0100, Roberto Sassu wrote: > > do you have any news on this bug?
Thanks for the reminder. Could you please try this patch?
---8<--- The helper mpi_read_raw_from_sgl ignores the second parameter nbytes when reading the SG list and may overrun its own buffer because it only allocates enough memory according to nbytes.
Fixes: 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers") Reported-by: Roberto Sassu <roberto.sassu@huaweicloud.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c index 39c4c6731094..6bffc68c1a5a 100644 --- a/lib/mpi/mpicoder.c +++ b/lib/mpi/mpicoder.c @@ -494,17 +494,15 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes) val->sign = 0; val->nlimbs = nlimbs; - if (nbytes == 0) - return val; - j = nlimbs - 1; a = 0; z = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB; z %= BYTES_PER_MPI_LIMB; - while (sg_miter_next(&miter)) { + while (nbytes && sg_miter_next(&miter)) { buff = miter.addr; - len = miter.length; + len = min_t(unsigned, miter.length, nbytes); + nbytes -= len; for (x = 0; x < len; x++) { a <<= 8; -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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