Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits Since commit e424054000878 ("MIPS: Tracing: Reduce the overhead of dynamic Function Tracer"), the macro UASM_i_LA_mostly has been used, and this macro can generate more than 2 instructions. At the same time, the code in ftrace assumes that no more than 2 instructions can be generated, which is why it stores them in an int[2] array. However, as previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA) causes a buffer overflow when _mcount is beyond 32 bits. This leads to corruption of the variables located in the __read_mostly section. This corruption was observed because the variable __cpu_primary_thread_mask was corrupted, causing a hang very early during boot. This fix prevents the corruption by avoiding the generation of instructions if they could exceed 2 instructions in length. Fortunately, insn_la_mcount is only used if the instrumented code is located outside the kernel code section, so dynamic ftrace can still be used, albeit in a more limited scope. This is still preferable to corrupting memory and/or crashing the kernel.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected e424054000878d7eb11e44289242886d6e219d22 before 9cfda98cf02eacfa6b09076e98bd479fd73407c2; affected e424054000878d7eb11e44289242886d6e219d22 before e3e33ac2eb69d595079a1a1e444c2fb98efdd42d; affected e424054000878d7eb11e44289242886d6e219d22 before 7f39b9d0e86ed6236b9a5fb67616ab1f76c4f150; affected e424054000878d7eb11e44289242886d6e219d22 before 36dac9a3dda1f2bae343191bc16b910c603cac25 |
| Linux / Linux | affected 2.6.35; unaffected 0 before 2.6.35; unaffected 6.6.160 through 6.6.*; unaffected 6.12.64 through 6.12.*; unaffected 6.18.3 through 6.18.*; unaffected 6.19 through * |
CWE
No CWE identifiers supplied.