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authorColin Ian King <colin.king@canonical.com>2015-02-23 11:34:10 +0000
committerTyler Hicks <tyhicks@canonical.com>2015-02-24 19:23:28 -0600
commit2a559a8bdeae853b6a8abb477c88875e1d4de591 (patch)
tree4adf5790e15b153640be45b30c3382c6ac7c6773 /fs/ecryptfs/main.c
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
eCryptfs: ensure copy to crypt_stat->cipher does not overrun
The patch 237fead61998: "[PATCH] ecryptfs: fs/Makefile and fs/Kconfig" from Oct 4, 2006, leads to the following static checker warning: fs/ecryptfs/crypto.c:846 ecryptfs_new_file_context() error: off-by-one overflow 'crypt_stat->cipher' size 32. rl = '0-32' There is a mismatch between the size of ecryptfs_crypt_stat.cipher and ecryptfs_mount_crypt_stat.global_default_cipher_name causing the copy of the cipher name to cause a off-by-one string copy error. This fix ensures the space reserved for this string is the same size including the trailing zero at the end throughout ecryptfs. This fix avoids increasing the size of ecryptfs_crypt_stat.cipher and also ecryptfs_parse_tag_70_packet_silly_stack.cipher_string and instead reduces the of ECRYPTFS_MAX_CIPHER_NAME_SIZE to 31 and includes the + 1 for the end of string terminator. NOTE: An overflow is not possible in practice since the value copied into global_default_cipher_name is validated by ecryptfs_code_for_cipher_string() at mount time. None of the allowed cipher strings are long enough to cause the potential buffer overflow fixed by this patch. Signed-off-by: Colin Ian King <colin.king@canonical.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> [tyhicks: Added the NOTE about the overflow not being triggerable] Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Diffstat (limited to 'fs/ecryptfs/main.c')
-rw-r--r--fs/ecryptfs/main.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 1895d60f4122..c095d3264259 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -407,7 +407,7 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
if (!cipher_name_set) {
int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
- BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+ BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
strcpy(mount_crypt_stat->global_default_cipher_name,
ECRYPTFS_DEFAULT_CIPHER);
}