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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.48% probability · 40th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/da353fac65fede6b8b4cfe207f0d9408e3121105Patch
- https://git.kernel.org/stable/c/e0cfd5159f314d6b304d030363650b06a2299cbbPatch
- https://git.kernel.org/stable/c/e41473543f75f7dbc5d605007e6f883f1bd13b9aPatch
- https://git.kernel.org/stable/c/f3dec7e7ace38224f82cf83f0049159d067c2e19Patch
- https://git.kernel.org/stable/c/da353fac65fede6b8b4cfe207f0d9408e3121105Patch
- https://git.kernel.org/stable/c/e0cfd5159f314d6b304d030363650b06a2299cbbPatch
- https://git.kernel.org/stable/c/e41473543f75f7dbc5d605007e6f883f1bd13b9aPatch
- https://git.kernel.org/stable/c/f3dec7e7ace38224f82cf83f0049159d067c2e19Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.