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| author | Theodore Ts'o <tytso@mit.edu> | 2016-11-18 19:00:24 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2016-11-18 19:00:24 +0100 |
| commit | 9e47a4c9fc58032ee135bf76516809c7624b1551 (patch) | |
| tree | da624f876cdb9cb1cfd4841007332b590fd385ed | |
| parent | ext4: remove parameter from ext4_xattr_ibody_set() (diff) | |
| download | linux-9e47a4c9fc58032ee135bf76516809c7624b1551.tar.xz linux-9e47a4c9fc58032ee135bf76516809c7624b1551.zip | |
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.h | 1 | ||||
| -rw-r--r-- | fs/ext4/super.c | 17 |
2 files changed, 17 insertions, 1 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 53d6d463ac4d..bdf1e5ee8642 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 35ccbdc2d64e..0f9ae4ce33d6 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3567,7 +3567,15 @@ 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; } @@ -3699,6 +3707,13 @@ 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 = |