media: dvb-usb-v2: af9035: Fix null-ptr-deref in af9035_i2c_master_xfer

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: media: dvb-usb-v2: af9035: Fix null-ptr-deref in af9035_i2c_master_xfer In af9035_i2c_master_xfer, msg is controlled by user. When msg[i].buf is null and msg[i].len is zero, former checks on msg[i].buf would be passed. Malicious data finally reach af9035_i2c_master_xfer. If accessing msg[i].buf[0] without sanity check, null ptr deref would happen. We add check on msg[i].len to prevent crash. Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")

References

• https://git.kernel.org/stable/c/b2f54ed7739dfdf42c4df0a11131aad7c8635464
• https://git.kernel.org/stable/c/fa58d9db5cad4bb7bb694b6837e3b96d87554f2b
• https://git.kernel.org/stable/c/b49c6e5dd236787f13a062ec528d724169f11152
• https://git.kernel.org/stable/c/6c01ef65de0b321b2db1ef9abf8f1d15862b937e
• https://git.kernel.org/stable/c/d9ef84a7c222497ecb5fdf93361c76931804825e
• https://git.kernel.org/stable/c/0143f282b15f7cedc0392ea10050fb6000fd16e6
• https://git.kernel.org/stable/c/41b7181a40af84448a2b144fb02d8bf32b7e9a23
• https://git.kernel.org/stable/c/7bf744f2de0a848fb1d717f5831b03db96feae89