From 7361d1bc307b926cbca214ab67b641123c2d6357 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 27 Dec 2022 15:27:39 +0100
Subject: [PATCH] lib/mpi: Fix buffer overrun when SG is too long
Git-commit: 7361d1bc307b926cbca214ab67b641123c2d6357
Patch-mainline: v6.3-rc1
References: git-fixes
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>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
lib/mpi/mpicoder.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
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;
--
2.35.3