Subject: [PATCH] commit.c: ensure strchrnul() doesn't scan beyond range

From: "Chandra Pratap via GitGitGadget" <[email-masked]>
Date: Mon, 05 Feb 2024 17:21:45 +0000

From: Chandra Pratap <[email-masked]>

Signed-off-by: Chandra Pratap <[email-masked]>
---
    commit.c: ensure strchrnul() doesn't scan beyond range

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1652%2FChand-ra%2Fstrchrnul-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1652/Chand-ra/strchrnul-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1652

 commit.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/commit.c b/commit.c
index ef679a0b939..a65b8e92e94 100644
--- a/commit.c
+++ b/commit.c
@@ -1743,15 +1743,9 @@ const char *find_header_mem(const char *msg, size_t len,
 	int key_len = strlen(key);
 	const char *line = msg;
 
-	/*
-	 * NEEDSWORK: It's possible for strchrnul() to scan beyond the range
-	 * given by len. However, current callers are safe because they compute
-	 * len by scanning a NUL-terminated block of memory starting at msg.
-	 * Nonetheless, it would be better to ensure the function does not look
-	 * at msg beyond the len provided by the caller.
-	 */
 	while (line && line < msg + len) {
 		const char *eol = strchrnul(line, '\n');
+		assert(eol - line <= len);
 
 		if (line == eol)
 			return NULL;

base-commit: a54a84b333adbecf7bc4483c0e36ed5878cac17b
-- 
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