This is a note to let you know that I've just added the patch titled MIPS: Consistently handle buffer counter with PTRACE_SETREGSET to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-consistently-handle-buffer-counter-with-ptrace_setregset.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 80b3ffce0196ea50068885d085ff981e4b8396f4 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro@xxxxxxxx> Date: Mon, 11 Dec 2017 22:53:14 +0000 Subject: MIPS: Consistently handle buffer counter with PTRACE_SETREGSET From: Maciej W. Rozycki <macro@xxxxxxxx> commit 80b3ffce0196ea50068885d085ff981e4b8396f4 upstream. Update commit d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") bug and consistently consume all data supplied to `fpr_set_msa' with the ptrace(2) PTRACE_SETREGSET request, such that a zero data buffer counter is returned where insufficient data has been given to fill a whole number of FP general registers. In reality this is not going to happen, as the caller is supposed to only supply data covering a whole number of registers and it is verified in `ptrace_regset' and again asserted in `fpr_set', however structuring code such that the presence of trailing partial FP general register data causes `fpr_set_msa' to return with a non-zero data buffer counter makes it appear that this trailing data will be used if there are subsequent writes made to FP registers, which is going to be the case with the FCSR once the missing write to that register has been fixed. Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxx> Cc: James Hogan <james.hogan@xxxxxxxx> Cc: Paul Burton <Paul.Burton@xxxxxxxx> Cc: Alex Smith <alex@xxxxxxxxxxxxxxxx> Cc: Dave Martin <Dave.Martin@xxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx # v4.11+ Patchwork: https://patchwork.linux-mips.org/patch/17927/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -485,7 +485,7 @@ static int fpr_set_msa(struct task_struc int err; BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t)); - for (i = 0; i < NUM_FPU_REGS && *count >= sizeof(elf_fpreg_t); i++) { + for (i = 0; i < NUM_FPU_REGS && *count > 0; i++) { err = user_regset_copyin(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t)); Patches currently in stable-queue which might be from macro@xxxxxxxx are queue-3.18/mips-consistently-handle-buffer-counter-with-ptrace_setregset.patch queue-3.18/mips-disallow-outsized-ptrace_setregset-nt_prfpreg-regset-accesses.patch queue-3.18/mips-guard-against-any-partial-write-attempt-with-ptrace_setregset.patch queue-3.18/mips-also-verify-sizeof-elf_fpreg_t-with-ptrace_setregset.patch queue-3.18/mips-factor-out-nt_prfpreg-regset-access-helpers.patch queue-3.18/mips-fix-an-fcsr-access-api-regression-with-nt_prfpreg-and-msa.patch