CVE-2021-47249: net: rds: fix memory leak in rds_recvmsg
First published: Tue May 21 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: net: rds: fix memory leak in rds_recvmsg Syzbot reported memory leak in rds. The problem was in unputted refcount in case of error. int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int msg_flags) { ... if (!rds_next_incoming(rs, &inc)) { ... } After this "if" inc refcount incremented and if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; goto out; } ... out: return ret; } in case of rds_cmsg_recv() fail the refcount won't be decremented. And it's easy to see from ftrace log, that rds_inc_addref() don't have rds_inc_put() pair in rds_recvmsg() after rds_cmsg_recv() 1) | rds_recvmsg() { 1) 3.721 us | rds_inc_addref(); 1) 3.853 us | rds_message_inc_copy_to_user(); 1) + 10.395 us | rds_cmsg_recv(); 1) + 34.260 us | }
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux kernel | >=2.6.30<4.4.274 | |
| Linux kernel | >=4.5<4.9.274 | |
| Linux kernel | >=4.10<4.14.238 | |
| Linux kernel | >=4.15<4.19.196 | |
| Linux kernel | >=4.20<5.4.128 | |
| Linux kernel | >=5.5<5.10.46 | |
| Linux kernel | >=5.11<5.12.13 | |
| Linux kernel | =5.13-rc1 | |
| Linux kernel | =5.13-rc2 | |
| Linux kernel | =5.13-rc3 | |
| Linux kernel | =5.13-rc4 | |
| Linux kernel | =5.13-rc5 | |
| Linux kernel | =5.13-rc6 |
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Reference Links
- https://git.kernel.org/stable/c/8c3ec88b03e9e4ca117dcdc4204fd3edcd02084f
- https://git.kernel.org/stable/c/423c6939758fb3b9cf5abbd1e7792068a5c4ae8c
- https://git.kernel.org/stable/c/1f79bc8ae81c05eb112a53f981cb2c244ee50d02
- https://git.kernel.org/stable/c/06b7cb0194bd1ede0dd27f3a946e7c0279fba44a
- https://git.kernel.org/stable/c/2038cd15eacdf7512755c27686822e0052eb9042
- https://git.kernel.org/stable/c/5946fbf48355f5a8caeff72580c7658da5966b86
- https://git.kernel.org/stable/c/b25b60d076164edb3025e85aabd2cf50a5215b91
- https://git.kernel.org/stable/c/49bfcbfd989a8f1f23e705759a6bb099de2cff9f
Frequently Asked Questions
What is the severity of CVE-2021-47249?
CVE-2021-47249 has a severity rating of moderate due to the potential memory leak affecting the Linux kernel.
How do I fix CVE-2021-47249?
To fix CVE-2021-47249, update your Linux kernel to the latest version that addresses this vulnerability.
Which versions of the Linux kernel are affected by CVE-2021-47249?
CVE-2021-47249 affects various versions of the Linux kernel from 2.6.30 to 5.13-rc6.
What is the impact of CVE-2021-47249 on my system?
The impact of CVE-2021-47249 is a memory leak in the RDS protocol, potentially leading to reduced system performance over time.
Is CVE-2021-47249 exploitable?
CVE-2021-47249 is not directly exploitable in a way that would allow remote code execution, but it can lead to system resource depletion.
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