diff options
authorDiego Calleja <diegocg@gmail.com>2006-11-20 22:25:17 +0100
committerAdrian Bunk <bunk@stusta.de>2006-11-20 22:25:17 +0100
commit2c8e2c9fe5a7f6952b2c16d934ee9cc112643f0f (patch)
parentfacabd6146f0622312f0493c80a3d26227cebf69 (diff)
Fix BeFS slab corruption
In bugzilla #6941, Jens Kilian reported: "The function befs_utf2nls (in fs/befs/linuxvfs.c) writes a 0 byte past the end of a block of memory allocated via kmalloc(), leading to memory corruption. This happens only for filenames which are pure ASCII and a multiple of 4 bytes in length. [...] Without DEBUG_SLAB, this leads to further corruption and hard lockups; I believe this is the bug which has made kernels later than 2.6.8 unusable for me. (This must be due to changes in memory management, the bug has been in the BeFS driver since the time it was introduced (AFAICT).) Steps to reproduce: Create a directory (in BeOS, naturally :-) with files named, e.g., "1", "22", "333", "4444", ... Mount it in Linux and do an "ls" or "find"" This patch implements the suggested fix. Credits to Jens Kilian for debugging the problem and finding the right fix. Signed-off-by: Diego Calleja <diegocg@gmail.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index 2d365cb8eec6..71aeffbd1eae 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -511,7 +511,11 @@ befs_utf2nls(struct super_block *sb, const char *in,
wchar_t uni;
int unilen, utflen;
char *result;
- int maxlen = in_len; /* The utf8->nls conversion can't make more chars */
+ /* The utf8->nls conversion won't make the final nls string bigger
+ * than the utf one, but if the string is pure ascii they'll have the
+ * same width and an extra char is needed to save the additional \0
+ */
+ int maxlen = in_len + 1;
befs_debug(sb, "---> utf2nls()");
@@ -587,7 +591,10 @@ befs_nls2utf(struct super_block *sb, const char *in,
wchar_t uni;
int unilen, utflen;
char *result;
- int maxlen = 3 * in_len;
+ /* There're nls characters that will translate to 3-chars-wide UTF-8
+ * characters, a additional byte is needed to save the final \0
+ * in special cases */
+ int maxlen = (3 * in_len) + 1;
befs_debug(sb, "---> nls2utf()\n");