2.1 KiB
CVE-2024-57874
Description
In the Linux kernel, the following vulnerability has been resolved:arm64: ptrace: fix partial SETREGSET for NT_ARM_TAGGED_ADDR_CTRLCurrently tagged_addr_ctrl_set() doesn't initialize the temporary 'ctrl'variable, and a SETREGSET call with a length of zero will leave thisuninitialized. Consequently tagged_addr_ctrl_set() will consume anarbitrary value, potentially leaking up to 64 bits of memory from thekernel stack. The read is limited to a specific slot on the stack, andthe issue does not provide a write mechanism.As set_tagged_addr_ctrl() only accepts values where bits [63:4] zero andrejects other values, a partial SETREGSET attempt will randomly succeedor fail depending on the value of the uninitialized value, and theexposure is significantly limited.Fix this by initializing the temporary value before copying the regsetfrom userspace, as for other regsets (e.g. NT_PRSTATUS, NT_PRFPREG,NT_ARM_SYSTEM_CALL). In the case of a zero-length write, the existingvalue of the tagged address ctrl will be retained.The NT_ARM_TAGGED_ADDR_CTRL regset is only visible in theuser_aarch64_view used by a native AArch64 task to manipulate anothernative AArch64 task. As get_tagged_addr_ctrl() only returns an errorvalue when called for a compat task, tagged_addr_ctrl_get() andtagged_addr_ctrl_set() should never observe an error value fromget_tagged_addr_ctrl(). Add a WARN_ON_ONCE() to both to indicate thatsuch an error would be unexpected, and error handlnig is not missing ineither case.
POC
Reference
No PoCs from references.