CVE-2021-47276

In the Linux kernel, the following vulnerability has been resolved: ftrace: Do not blindly read the ip address in ftrace_bug() It was reported that a bug on arm64 caused a bad ip address to be used for updating into a nop in ftrace_init(), but the error path (rightfully) returned -EINVAL and not -EFAULT, as the bug caused more than one error to occur. But because -EINVAL was returned, the ftrace_bug() tried to report what was at the location of the ip address, and read it directly. This caused the machine to panic, as the ip was not pointing to a valid memory address. Instead, read the ip address with copy_from_kernel_nofault() to safely access the memory, and if it faults, report that the address faulted, otherwise report what was in that location.

• linux linux kernel (>= 2.6.28 < 4.4.273) • linux linux kernel (>= 4.5 < 4.9.273) • linux linux kernel (>= 4.10 < 4.14.237) • linux linux kernel (>= 4.15 < 4.19.195) • linux linux kernel (>= 4.20 < 5.4.126) • linux linux kernel (>= 5.5 < 5.10.44) • linux linux kernel (>= 5.11 < 5.12.11) • linux linux kernel 5.13