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| author | Liu Song <liu.song11@zte.com.cn> | 2020-01-16 18:36:07 +0300 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2020-03-31 00:02:37 +0300 |
| commit | acc5af3efa303d5f36cc8c0f61716161f6ca1384 (patch) | |
| tree | 071f542397119ebef35bd95886f79fd931a181aa /fs/ubifs | |
| parent | 294a8dbe34d3b2f6e48eb9058ed21d7fe9348b6b (diff) | |
| download | linux-acc5af3efa303d5f36cc8c0f61716161f6ca1384.tar.xz | |
ubifs: Fix out-of-bounds memory access caused by abnormal value of node_len
In “ubifs_check_node”, when the value of "node_len" is abnormal,
the code will goto label of "out_len" for execution. Then, in the
following "ubifs_dump_node", if inode type is "UBIFS_DATA_NODE",
in "print_hex_dump", an out-of-bounds access may occur due to the
wrong "ch->len".
Therefore, when the value of "node_len" is abnormal, data length
should to be adjusted to a reasonable safe range. At this time,
structured data is not credible, so dump the corrupted data directly
for analysis.
Signed-off-by: Liu Song <liu.song11@zte.com.cn>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'fs/ubifs')
| -rw-r--r-- | fs/ubifs/io.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c index 8ceb51478800..7e4bfaf2871f 100644 --- a/fs/ubifs/io.c +++ b/fs/ubifs/io.c @@ -225,7 +225,7 @@ int ubifs_is_mapped(const struct ubifs_info *c, int lnum) int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum, int offs, int quiet, int must_chk_crc) { - int err = -EINVAL, type, node_len; + int err = -EINVAL, type, node_len, dump_node = 1; uint32_t crc, node_crc, magic; const struct ubifs_ch *ch = buf; @@ -278,10 +278,22 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum, out_len: if (!quiet) ubifs_err(c, "bad node length %d", node_len); + if (type == UBIFS_DATA_NODE && node_len > UBIFS_DATA_NODE_SZ) + dump_node = 0; out: if (!quiet) { ubifs_err(c, "bad node at LEB %d:%d", lnum, offs); - ubifs_dump_node(c, buf); + if (dump_node) { + ubifs_dump_node(c, buf); + } else { + int safe_len = min3(node_len, c->leb_size - offs, + (int)UBIFS_MAX_DATA_NODE_SZ); + pr_err("\tprevent out-of-bounds memory access\n"); + pr_err("\ttruncated data node length %d\n", safe_len); + pr_err("\tcorrupted data node:\n"); + print_hex_dump(KERN_ERR, "\t", DUMP_PREFIX_OFFSET, 32, 1, + buf, safe_len, 0); + } dump_stack(); } return err; |