* [PATCH] mtd-utils: fixes double free in mkfs.ubifs
@ 2019-01-24 9:06 Yufen Yu
2019-02-11 5:21 ` David Oberhollenzer
0 siblings, 1 reply; 2+ messages in thread
From: Yufen Yu @ 2019-01-24 9:06 UTC (permalink / raw)
To: linux-mtd, richard, david.oberhollenzer
In inode_add_xattr(), it malloc a buffer for name, and then passes
the bufffer ptr to add_xattr(). The ptr will be used to create a new
idx_entry in add_to_index().
However, inode_add_xattr() will free the buffer before return.
which can cause double free in write_index(): free(idx_ptr[i]->name)
*** Error in `./mkfs.ubifs': double free or corruption (fasttop): 0x0000000000aae220 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7cbac)[0x7f4881ff5bac]
/lib64/libc.so.6(+0x87a59)[0x7f4882000a59]
/lib64/libc.so.6(cfree+0x16e)[0x7f48820063be]
./mkfs.ubifs[0x402fbf]
/lib64/libc.so.6(__libc_start_main+0xea)[0x7f4881f9988a]
./mkfs.ubifs[0x40356a]
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
ubifs-utils/mkfs.ubifs/mkfs.ubifs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c b/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c
index 6e11ec8..e0c42f3 100644
--- a/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c
+++ b/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c
@@ -1163,8 +1163,9 @@ static int add_xattr(struct ubifs_ino_node *host_ino, struct stat *st,
union ubifs_key xkey, nkey;
int len, ret;
- nm.name = name;
nm.len = strlen(name);
+ nm.name = xmalloc(nm.len + 1);
+ memcpy(nm.name, name, nm.len + 1);
host_ino->xattr_cnt++;
host_ino->xattr_size += CALC_DENT_SIZE(nm.len);
--
2.13.6
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2019-01-24 9:06 [PATCH] mtd-utils: fixes double free in mkfs.ubifs Yufen Yu
2019-02-11 5:21 ` David Oberhollenzer
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