diff mbox series

[v4,1/2] lib/mpi: Fix buffer overrun when SG is too long

Message ID 20221227094632.2797203-1-roberto.sassu@huaweicloud.com (mailing list archive)
State New
Headers show
Series [v4,1/2] lib/mpi: Fix buffer overrun when SG is too long | expand

Commit Message

Roberto Sassu Dec. 27, 2022, 9:46 a.m. UTC 
From: Herbert Xu <herbert@gondor.apana.org.au>

The helper mpi_read_raw_from_sgl sets the number of entries in
the SG list according to nbytes.  However, if the last entry
in the SG list contains more data than nbytes, then it may overrun
the buffer because it only allocates enough memory for 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>
---
 lib/mpi/mpicoder.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index 39c4c6731094..3cb6bd148fa9 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -504,7 +504,8 @@  MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
 
 	while (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;