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authorTheodore Ts'o <tytso@mit.edu>2016-11-18 13:00:24 -0500
committerTheodore Ts'o <tytso@mit.edu>2016-11-19 20:58:15 -0500
commit8cdf3372fe8368f56315e66bea9f35053c418093 (patch)
treece03e6d1c641f2eac33bb811c1ac260c8b2d2c23
parent0f0909e242f73c1154272cf04f07fc9afe13e5b8 (diff)
downloadlinux-stericsson-8cdf3372fe8368f56315e66bea9f35053c418093.tar.gz
ext4: sanity check the block and cluster size at mount time
If the block size or cluster size is insane, reject the mount. This is important for security reasons (although we shouldn't be just depending on this check). Ref: http://www.securityfocus.com/archive/1/539661 Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1332506 Reported-by: Borislav Petkov <bp@alien8.de> Reported-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
-rw-r--r--fs/ext4/ext4.h1
-rw-r--r--fs/ext4/super.c17
2 files changed, 17 insertions, 1 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 282a51b07c57..a8a750f59621 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -235,6 +235,7 @@ struct ext4_io_submit {
#define EXT4_MAX_BLOCK_SIZE 65536
#define EXT4_MIN_BLOCK_LOG_SIZE 10
#define EXT4_MAX_BLOCK_LOG_SIZE 16
+#define EXT4_MAX_CLUSTER_LOG_SIZE 30
#ifdef __KERNEL__
# define EXT4_BLOCK_SIZE(s) ((s)->s_blocksize)
#else
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 20da99da0a34..52b0530c5d65 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3565,7 +3565,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
if (blocksize < EXT4_MIN_BLOCK_SIZE ||
blocksize > EXT4_MAX_BLOCK_SIZE) {
ext4_msg(sb, KERN_ERR,
- "Unsupported filesystem blocksize %d", blocksize);
+ "Unsupported filesystem blocksize %d (%d log_block_size)",
+ blocksize, le32_to_cpu(es->s_log_block_size));
+ goto failed_mount;
+ }
+ if (le32_to_cpu(es->s_log_block_size) >
+ (EXT4_MAX_BLOCK_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
+ ext4_msg(sb, KERN_ERR,
+ "Invalid log block size: %u",
+ le32_to_cpu(es->s_log_block_size));
goto failed_mount;
}
@@ -3697,6 +3705,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
"block size (%d)", clustersize, blocksize);
goto failed_mount;
}
+ if (le32_to_cpu(es->s_log_cluster_size) >
+ (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
+ ext4_msg(sb, KERN_ERR,
+ "Invalid log cluster size: %u",
+ le32_to_cpu(es->s_log_cluster_size));
+ goto failed_mount;
+ }
sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
le32_to_cpu(es->s_log_block_size);
sbi->s_clusters_per_group =