From d650bfc5cb35442cd47378c7dcb8eba8915fe564 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 27 Dec 2022 15:27:39 +0100 Subject: [PATCH] lib/mpi: Fix buffer overrun when SG is too long [ Upstream commit b29eaa3a12091c711801a8fd46e1687cc19e6456 ] 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: ebd84f3efad6 ("lib/mpi: Add mpi sgl helpers") Reported-by: Roberto Sassu Signed-off-by: Herbert Xu Reviewed-by: Eric Biggers Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- 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 39c4c67310946..3cb6bd148fa9e 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; -- 2.39.5