From 1526f3c9884c4e4bc15224bd25eacdb3f6e80cd2 Mon Sep 17 00:00:00 2001 From: Ricardo Robaina Date: Mon, 20 Jul 2026 20:44:48 -0400 Subject: [PATCH] audit: fix potential integer overflow in audit_log_n_hex() [ Upstream commit 65dfde57d1e29ce2b76fc23dd565eccd5c0bc0f0 ] The function calculates new_len as len << 1 for hex encoding. This has two overflow risks: the shift itself can overflow when len is large, and the result can be truncated when assigned to new_len (declared as int) from the size_t calculation. Fix by using check_shl_overflow() to catch shift overflow and changing new_len and loop counter i to size_t to prevent truncation. Cc: stable@vger.kernel.org Fixes: 168b7173959f ("AUDIT: Clean up logging of untrusted strings") Reviewed-by: Richard Guy Briggs Signed-off-by: Ricardo Robaina [PM: remove vertical whitspace noise] Signed-off-by: Paul Moore Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/audit.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index ffe3694137ae..20b71a5b4760 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -59,6 +59,7 @@ #include #include #include +#include #include "audit.h" @@ -2034,7 +2035,8 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, size_t len) { - int i, avail, new_len; + int avail; + size_t i, new_len; unsigned char *ptr; struct sk_buff *skb; @@ -2044,7 +2046,12 @@ void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, BUG_ON(!ab->skb); skb = ab->skb; avail = skb_tailroom(skb); - new_len = len<<1; + + if (check_shl_overflow(len, 1, &new_len)) { + audit_log_format(ab, "?"); + return; + } + if (new_len >= avail) { /* Round the buffer request up to the next multiple */ new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);