From 70165dc3ec8cff702da7b8b122c44575ee3111d6 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 2 Oct 2025 04:26:20 -0700 Subject: [PATCH] crypto: sha256 - fix crash at kexec Loading a large (~2.1G) files with kexec crashes the host with when running: # kexec --load kernel --initrd initrd_with_2G_or_more UBSAN: signed-integer-overflow in ./include/crypto/sha256_base.h:64:19 34152083 * 64 cannot be represented in type 'int' ... BUG: unable to handle page fault for address: ff9fffff83b624c0 sha256_update (lib/crypto/sha256.c:137) crypto_sha256_update (crypto/sha256_generic.c:40) kexec_calculate_store_digests (kernel/kexec_file.c:769) __se_sys_kexec_file_load (kernel/kexec_file.c:397 kernel/kexec_file.c:332) ... (Line numbers based on commit da274362a7bd9 ("Linux 6.12.49") This started happening after commit f4da7afe07523f ("kexec_file: increase maximum file size to 4G") that landed in v6.0, which increased the file size for kexec. This is not happening upstream (v6.16+), given that `block` type was upgraded from "int" to "size_t" in commit 74a43a2cf5e8 ("crypto: lib/sha256 - Move partial block handling out") Upgrade the block type similar to the commit above, avoiding hitting the overflow. This patch is only suitable for the stable tree, and before 6.16, which got commit 74a43a2cf5e8 ("crypto: lib/sha256 - Move partial block handling out"). This is not required before f4da7afe07523f ("kexec_file: increase maximum file size to 4G"). In other words, this fix is required between versions v6.0 and v6.16. Signed-off-by: Breno Leitao Fixes: f4da7afe07523f ("kexec_file: increase maximum file size to 4G") # Before v6.16 Reported-by: Michael van der Westhuizen Reported-by: Tobias Fleig Reviewed-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- include/crypto/sha256_base.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/crypto/sha256_base.h b/include/crypto/sha256_base.h index e0418818d63c..e3e610cfe8d3 100644 --- a/include/crypto/sha256_base.h +++ b/include/crypto/sha256_base.h @@ -44,7 +44,7 @@ static inline int lib_sha256_base_do_update(struct sha256_state *sctx, sctx->count += len; if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) { - int blocks; + unsigned int blocks; if (partial) { int p = SHA256_BLOCK_SIZE - partial;