Vulnerability Details : CVE-2021-47496
In the Linux kernel, the following vulnerability has been resolved:
net/tls: Fix flipped sign in tls_err_abort() calls
sk->sk_err appears to expect a positive value, a convention that ktls
doesn't always follow and that leads to memory corruption in other code.
For instance,
[kworker]
tls_encrypt_done(..., err=<negative error from crypto request>)
tls_err_abort(.., err)
sk->sk_err = err;
[task]
splice_from_pipe_feed
...
tls_sw_do_sendpage
if (sk->sk_err) {
ret = -sk->sk_err; // ret is positive
splice_from_pipe_feed (continued)
ret = actor(...) // ret is still positive and interpreted as bytes
// written, resulting in underflow of buf->len and
// sd->len, leading to huge buf->offset and bogus
// addresses computed in later calls to actor()
Fix all tls_err_abort() callers to pass a negative error code
consistently and centralize the error-prone sign flip there, throwing in
a warning to catch future misuse and uninlining the function so it
really does only warn once.
Vulnerability category: Memory Corruption
Products affected by CVE-2021-47496
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Exploit prediction scoring system (EPSS) score for CVE-2021-47496
0.07%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 19 %
Percentile, the proportion of vulnerabilities that are scored at or less
References for CVE-2021-47496
-
https://git.kernel.org/stable/c/e0cfd5159f314d6b304d030363650b06a2299cbb
net/tls: Fix flipped sign in tls_err_abort() calls - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/da353fac65fede6b8b4cfe207f0d9408e3121105
net/tls: Fix flipped sign in tls_err_abort() calls - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/e41473543f75f7dbc5d605007e6f883f1bd13b9a
net/tls: Fix flipped sign in tls_err_abort() calls - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/f3dec7e7ace38224f82cf83f0049159d067c2e19
net/tls: Fix flipped sign in tls_err_abort() calls - kernel/git/stable/linux.git - Linux kernel stable tree
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