From: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Ryusuke Konishi
<konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH AUTOSEL 5.10 7/9] nilfs2: fix shift-out-of-bounds due to too large exponent of block size
Date: Sat, 17 Dec 2022 10:29:24 -0500 [thread overview]
Message-ID: <20221217152927.99012-7-sashal@kernel.org> (raw)
In-Reply-To: <20221217152927.99012-1-sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
From: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
[ Upstream commit ebeccaaef67a4895d2496ab8d9c2fb8d89201211 ]
If field s_log_block_size of superblock data is corrupted and too large,
init_nilfs() and load_nilfs() still can trigger a shift-out-of-bounds
warning followed by a kernel panic (if panic_on_warn is set):
shift exponent 38973 is too large for 32-bit type 'int'
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
ubsan_epilogue+0xb/0x50
__ubsan_handle_shift_out_of_bounds.cold.12+0x17b/0x1f5
init_nilfs.cold.11+0x18/0x1d [nilfs2]
nilfs_mount+0x9b5/0x12b0 [nilfs2]
...
This fixes the issue by adding and using a new helper function for getting
block size with sanity check.
Link: https://lkml.kernel.org/r/20221027044306.42774-3-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Tested-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
fs/nilfs2/the_nilfs.c | 42 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 38 insertions(+), 4 deletions(-)
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 6e2ccdd79c89..211937054c31 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -193,6 +193,34 @@ static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
return ret;
}
+/**
+ * nilfs_get_blocksize - get block size from raw superblock data
+ * @sb: super block instance
+ * @sbp: superblock raw data buffer
+ * @blocksize: place to store block size
+ *
+ * nilfs_get_blocksize() calculates the block size from the block size
+ * exponent information written in @sbp and stores it in @blocksize,
+ * or aborts with an error message if it's too large.
+ *
+ * Return Value: On success, 0 is returned. If the block size is too
+ * large, -EINVAL is returned.
+ */
+static int nilfs_get_blocksize(struct super_block *sb,
+ struct nilfs_super_block *sbp, int *blocksize)
+{
+ unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
+
+ if (unlikely(shift_bits >
+ ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) {
+ nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB",
+ shift_bits);
+ return -EINVAL;
+ }
+ *blocksize = BLOCK_SIZE << shift_bits;
+ return 0;
+}
+
/**
* load_nilfs - load and recover the nilfs
* @nilfs: the_nilfs structure to be released
@@ -246,11 +274,15 @@ int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
/* verify consistency between two super blocks */
- blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
+ err = nilfs_get_blocksize(sb, sbp[0], &blocksize);
+ if (err)
+ goto scan_error;
+
if (blocksize != nilfs->ns_blocksize) {
nilfs_warn(sb,
"blocksize differs between two super blocks (%d != %d)",
blocksize, nilfs->ns_blocksize);
+ err = -EINVAL;
goto scan_error;
}
@@ -609,9 +641,11 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
if (err)
goto failed_sbh;
- blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
- if (blocksize < NILFS_MIN_BLOCK_SIZE ||
- blocksize > NILFS_MAX_BLOCK_SIZE) {
+ err = nilfs_get_blocksize(sb, sbp, &blocksize);
+ if (err)
+ goto failed_sbh;
+
+ if (blocksize < NILFS_MIN_BLOCK_SIZE) {
nilfs_err(sb,
"couldn't mount because of unsupported filesystem blocksize %d",
blocksize);
--
2.35.1
prev parent reply other threads:[~2022-12-17 15:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20221217152927.99012-1-sashal@kernel.org>
[not found] ` <20221217152927.99012-1-sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 6/9] nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset() Sasha Levin
2022-12-17 15:29 ` Sasha Levin [this message]
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