[PATCH] fs: ext4: Fix dereferencing the null pointer 'ptr'

23 Nov 2022

If memory allocation fails on line 780, then 'fail' will be
 jumped to and 'ptr' will be null, causing it to be dereferenced it on line
 855. Thus, before using 'ptr[i]' one must make sure that the 'ptr' pointer
 is not NULL.
Fixes: 934b14f2bb30 ("ext4: free allocations by parse_path()")
Signed-off-by: Mikhail Ilin ilin.mikhail.ol@gmail.com
---
 fs/ext4/ext4_common.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 1185cb2c04..3cdd1a04a9 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -851,10 +851,12 @@ end:
 fail:
    free(depth_dirname);
    free(parse_dirname);
-	for (i = 0; i < depth; i++) {
-		if (!ptr[i])
-			break;
-		free(ptr[i]);
+	if (ptr) {
+		for (i = 0; i < depth; i++) {
+			if (!ptr[i])
+				break;
+			free(ptr[i]);
+		}
    }
    free(ptr);
    free(parent_inode);
-- 
2.17.1


    

Mikhail Ilin

Stefan Roese

tags (0)

participants (2)