+ tools-mm-slabinfo-fix-access-to-null-terminator-in-string-boundary.patch added to mm-new branch

+ tools-mm-slabinfo-fix-access-to-null-terminator-in-string-boundary.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: tools/mm/slabinfo: fix access to null terminator in string boundary
has been added to the -mm mm-new branch.  Its filename is
     tools-mm-slabinfo-fix-access-to-null-terminator-in-string-boundary.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tools-mm-slabinfo-fix-access-to-null-terminator-in-string-boundary.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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patches, and acceptance into mm-new is a notification for others take
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------------------------------------------------------
From: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Subject: tools/mm/slabinfo: fix access to null terminator in string boundary
Date: Sat, 30 Aug 2025 22:50:22 +0530

The current code incorrectly accesses buffer[strlen(buffer)], which points
to the null terminator ('\0') at the end of the string.  This is
technically out-of-bounds access since valid string content ends at index
strlen(buffer)-1.

Fix by:
1. Declaring strlen() result variable at function scope
2. Adding bounds check (len > 0) to handle empty strings
3. Using buffer[len-1] to correctly access the last character before
   the null terminator

Link: https://lkml.kernel.org/r/20250830172022.1927448-1-kaushlendra.kumar@intel.com
Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/mm/slabinfo.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/tools/mm/slabinfo.c~tools-mm-slabinfo-fix-access-to-null-terminator-in-string-boundary
+++ a/tools/mm/slabinfo.c
@@ -155,6 +155,8 @@ static void usage(void)
 
 static unsigned long read_obj(const char *name)
 {
+	size_t len;
+
 	FILE *f = fopen(name, "r");
 
 	if (!f) {
@@ -165,8 +167,10 @@ static unsigned long read_obj(const char
 		if (!fgets(buffer, sizeof(buffer), f))
 			buffer[0] = 0;
 		fclose(f);
-		if (buffer[strlen(buffer)] == '\n')
-			buffer[strlen(buffer)] = 0;
+		len = strlen(buffer);
+
+		if (len > 0 && buffer[len - 1] == '\n')
+			buffer[len - 1] = 0;
 	}
 	return strlen(buffer);
 }
_

Patches currently in -mm which might be from kaushlendra.kumar@intel.com are

tools-mm-slabinfo-fix-access-to-null-terminator-in-string-boundary.patch