From a4dad1ae24f850410c4e60f22823cba1289b8d52 Mon Sep 17 00:00:00 2001 From: David Turner Date: Tue, 24 Nov 2015 14:34:37 -0500 Subject: ext4: Fix handling of extended tv_sec In ext4, the bottom two bits of {a,c,m}time_extra are used to extend the {a,c,m}time fields, deferring the year 2038 problem to the year 2446. When decoding these extended fields, for times whose bottom 32 bits would represent a negative number, sign extension causes the 64-bit extended timestamp to be negative as well, which is not what's intended. This patch corrects that issue, so that the only negative {a,c,m}times are those between 1901 and 1970 (as per 32-bit signed timestamps). Some older kernels might have written pre-1970 dates with 1,1 in the extra bits. This patch treats those incorrectly-encoded dates as pre-1970, instead of post-2311, until kernel 4.20 is released. Hopefully by then e2fsck will have fixed up the bad data. Also add a comment explaining the encoding of ext4's extra {a,c,m}time bits. Signed-off-by: David Turner Signed-off-by: Theodore Ts'o Reported-by: Mark Harris Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=23732 Cc: stable@vger.kernel.org --- fs/ext4/ext4.h | 51 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 44 insertions(+), 7 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 750063f7a50c..cc7ca4e87144 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -727,19 +728,55 @@ struct move_extent { <= (EXT4_GOOD_OLD_INODE_SIZE + \ (einode)->i_extra_isize)) \ +/* + * We use an encoding that preserves the times for extra epoch "00": + * + * extra msb of adjust for signed + * epoch 32-bit 32-bit tv_sec to + * bits time decoded 64-bit tv_sec 64-bit tv_sec valid time range + * 0 0 1 -0x80000000..-0x00000001 0x000000000 1901-12-13..1969-12-31 + * 0 0 0 0x000000000..0x07fffffff 0x000000000 1970-01-01..2038-01-19 + * 0 1 1 0x080000000..0x0ffffffff 0x100000000 2038-01-19..2106-02-07 + * 0 1 0 0x100000000..0x17fffffff 0x100000000 2106-02-07..2174-02-25 + * 1 0 1 0x180000000..0x1ffffffff 0x200000000 2174-02-25..2242-03-16 + * 1 0 0 0x200000000..0x27fffffff 0x200000000 2242-03-16..2310-04-04 + * 1 1 1 0x280000000..0x2ffffffff 0x300000000 2310-04-04..2378-04-22 + * 1 1 0 0x300000000..0x37fffffff 0x300000000 2378-04-22..2446-05-10 + * + * Note that previous versions of the kernel on 64-bit systems would + * incorrectly use extra epoch bits 1,1 for dates between 1901 and + * 1970. e2fsck will correct this, assuming that it is run on the + * affected filesystem before 2242. + */ + static inline __le32 ext4_encode_extra_time(struct timespec *time) { - return cpu_to_le32((sizeof(time->tv_sec) > 4 ? - (time->tv_sec >> 32) & EXT4_EPOCH_MASK : 0) | - ((time->tv_nsec << EXT4_EPOCH_BITS) & EXT4_NSEC_MASK)); + u32 extra = sizeof(time->tv_sec) > 4 ? + ((time->tv_sec - (s32)time->tv_sec) >> 32) & EXT4_EPOCH_MASK : 0; + return cpu_to_le32(extra | (time->tv_nsec << EXT4_EPOCH_BITS)); } static inline void ext4_decode_extra_time(struct timespec *time, __le32 extra) { - if (sizeof(time->tv_sec) > 4) - time->tv_sec |= (__u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK) - << 32; - time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS; + if (unlikely(sizeof(time->tv_sec) > 4 && + (extra & cpu_to_le32(EXT4_EPOCH_MASK)))) { +#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0) + /* Handle legacy encoding of pre-1970 dates with epoch + * bits 1,1. We assume that by kernel version 4.20, + * everyone will have run fsck over the affected + * filesystems to correct the problem. (This + * backwards compatibility may be removed before this + * time, at the discretion of the ext4 developers.) + */ + u64 extra_bits = le32_to_cpu(extra) & EXT4_EPOCH_MASK; + if (extra_bits == 3 && ((time->tv_sec) & 0x80000000) != 0) + extra_bits = 0; + time->tv_sec += extra_bits << 32; +#else + time->tv_sec += (u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK) << 32; +#endif + } + time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS; } #define EXT4_INODE_SET_XTIME(xtime, inode, raw_inode) \ -- cgit v1.2.3 From e2c9e0b28e146c9a3bce21408f3c02e24ac7ac31 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 26 Nov 2015 15:20:19 -0500 Subject: ext4: fix an endianness bug in ext4_encrypted_zeroout() ex->ee_block is not host-endian (note that accesses of other fields of *ex right next to that line go through the helpers that do proper conversion from little-endian to host-endian; it might make sense to add similar for ->ee_block to avoid reintroducing that kind of bugs...) Cc: stable@vger.kernel.org # v4.1+ Signed-off-by: Al Viro Signed-off-by: Theodore Ts'o --- fs/ext4/crypto.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4') diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index af06830bfc00..1a0835073663 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -389,7 +389,7 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) struct ext4_crypto_ctx *ctx; struct page *ciphertext_page = NULL; struct bio *bio; - ext4_lblk_t lblk = ex->ee_block; + ext4_lblk_t lblk = le32_to_cpu(ex->ee_block); ext4_fsblk_t pblk = ext4_ext_pblock(ex); unsigned int len = ext4_ext_get_actual_len(ex); int ret, err = 0; -- cgit v1.2.3 From 5a1c7f47da9b32d0671e776b0f388095b7f91e2e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 26 Nov 2015 15:20:50 -0500 Subject: ext4: fix an endianness bug in ext4_encrypted_follow_link() applying le32_to_cpu() to 16bit value is a bad idea... Cc: stable@vger.kernel.org # v4.1+ Signed-off-by: Al Viro Signed-off-by: Theodore Ts'o --- fs/ext4/symlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4') diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c index abe2401ce405..e8e7af62ac95 100644 --- a/fs/ext4/symlink.c +++ b/fs/ext4/symlink.c @@ -52,7 +52,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook /* Symlink is encrypted */ sd = (struct ext4_encrypted_symlink_data *)caddr; cstr.name = sd->encrypted_path; - cstr.len = le32_to_cpu(sd->len); + cstr.len = le16_to_cpu(sd->len); if ((cstr.len + sizeof(struct ext4_encrypted_symlink_data) - 1) > max_size) { -- cgit v1.2.3 From 681c46b164d79aaa5d18f7519b39e29f9b441e40 Mon Sep 17 00:00:00 2001 From: Xu Cang Date: Thu, 26 Nov 2015 15:52:24 -0500 Subject: ext4: add "static" to ext4_seq_##name##_fops struct to fix sparse warning, add static to ext4_seq_##name##_fops struct. Signed-off-by: Theodore Ts'o --- fs/ext4/sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4') diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index 1b57c72f4a00..1420a3c614af 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -358,7 +358,7 @@ static int name##_open(struct inode *inode, struct file *file) \ return single_open(file, ext4_seq_##name##_show, PDE_DATA(inode)); \ } \ \ -const struct file_operations ext4_seq_##name##_fops = { \ +static const struct file_operations ext4_seq_##name##_fops = { \ .owner = THIS_MODULE, \ .open = name##_open, \ .read = seq_read, \ -- cgit v1.2.3