Merge branch 'regset' (PTRACE_SETREGSET data leakage)
Merge PTRACE_SETREGSET leakage fixes from Dave Martin: "This series is the collection of fixes I proposed on this topic, that have not yet appeared upstream or in the stable branches, The issue can leak kernel stack, but doesn't appear to allow userspace to attack the kernel directly. The affected architectures are c6x, h8300, metag, mips and sparc. [ Mark Salter points out that c6x has no MMU or other mechanism to prevent userspace access to kernel code or data on c6x, but it doesn't hurt to clean that case up too. ] The bugs arise from use of user_regset_copyin(). Users of user_regset_copyin() can work in one of two ways: 1) Copy directly to thread_struct or equivalent. (This seems to be the design assumption of the regset API, and is the most common approach.) 2) Copy to a local variable and then transfer to thread_struct. (A significant minority of cases.) Buggy code typically involves approach 2" * emailed patches from Dave Martin <Dave.Martin@arm.com>: sparc/ptrace: Preserve previous registers for short regset write mips/ptrace: Preserve previous registers for short regset write metag/ptrace: Reject partial NT_METAG_RPIPE writes metag/ptrace: Provide default TXSTATUS for short NT_PRSTATUS metag/ptrace: Preserve previous registers for short regset write h8300/ptrace: Fix incorrect register transfer count c6x/ptrace: Remove useless PTRACE_SETREGSET implementation
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commit
72c33734b5
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@ -70,46 +70,6 @@ static int gpr_get(struct task_struct *target,
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0, sizeof(*regs));
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}
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static int gpr_set(struct task_struct *target,
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const struct user_regset *regset,
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unsigned int pos, unsigned int count,
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const void *kbuf, const void __user *ubuf)
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{
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int ret;
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struct pt_regs *regs = task_pt_regs(target);
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/* Don't copyin TSR or CSR */
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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®s,
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0, PT_TSR * sizeof(long));
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if (ret)
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return ret;
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ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
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PT_TSR * sizeof(long),
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(PT_TSR + 1) * sizeof(long));
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if (ret)
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return ret;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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®s,
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(PT_TSR + 1) * sizeof(long),
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PT_CSR * sizeof(long));
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if (ret)
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return ret;
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ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
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PT_CSR * sizeof(long),
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(PT_CSR + 1) * sizeof(long));
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if (ret)
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return ret;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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®s,
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(PT_CSR + 1) * sizeof(long), -1);
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return ret;
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}
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enum c6x_regset {
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REGSET_GPR,
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};
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@ -121,7 +81,6 @@ static const struct user_regset c6x_regsets[] = {
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.size = sizeof(u32),
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.align = sizeof(u32),
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.get = gpr_get,
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.set = gpr_set
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},
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};
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@ -95,7 +95,8 @@ static int regs_get(struct task_struct *target,
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long *reg = (long *)®s;
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/* build user regs in buffer */
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for (r = 0; r < ARRAY_SIZE(register_offset); r++)
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BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);
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for (r = 0; r < sizeof(regs) / sizeof(long); r++)
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*reg++ = h8300_get_reg(target, r);
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return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
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@ -113,7 +114,8 @@ static int regs_set(struct task_struct *target,
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long *reg;
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/* build user regs in buffer */
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for (reg = (long *)®s, r = 0; r < ARRAY_SIZE(register_offset); r++)
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BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);
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for (reg = (long *)®s, r = 0; r < sizeof(regs) / sizeof(long); r++)
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*reg++ = h8300_get_reg(target, r);
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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@ -122,7 +124,7 @@ static int regs_set(struct task_struct *target,
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return ret;
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/* write back to pt_regs */
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for (reg = (long *)®s, r = 0; r < ARRAY_SIZE(register_offset); r++)
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for (reg = (long *)®s, r = 0; r < sizeof(regs) / sizeof(long); r++)
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h8300_put_reg(target, r, *reg++);
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return 0;
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}
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@ -26,6 +26,16 @@
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* user_regset definitions.
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*/
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static unsigned long user_txstatus(const struct pt_regs *regs)
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{
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unsigned long data = (unsigned long)regs->ctx.Flags;
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if (regs->ctx.SaveMask & TBICTX_CBUF_BIT)
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data |= USER_GP_REGS_STATUS_CATCH_BIT;
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return data;
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}
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int metag_gp_regs_copyout(const struct pt_regs *regs,
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unsigned int pos, unsigned int count,
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void *kbuf, void __user *ubuf)
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@ -64,9 +74,7 @@ int metag_gp_regs_copyout(const struct pt_regs *regs,
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if (ret)
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goto out;
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/* TXSTATUS */
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data = (unsigned long)regs->ctx.Flags;
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if (regs->ctx.SaveMask & TBICTX_CBUF_BIT)
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data |= USER_GP_REGS_STATUS_CATCH_BIT;
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data = user_txstatus(regs);
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ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
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&data, 4*25, 4*26);
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if (ret)
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@ -121,6 +129,7 @@ int metag_gp_regs_copyin(struct pt_regs *regs,
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if (ret)
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goto out;
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/* TXSTATUS */
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data = user_txstatus(regs);
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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&data, 4*25, 4*26);
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if (ret)
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@ -246,6 +255,8 @@ int metag_rp_state_copyin(struct pt_regs *regs,
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unsigned long long *ptr;
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int ret, i;
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if (count < 4*13)
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return -EINVAL;
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/* Read the entire pipeline before making any changes */
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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&rp, 0, 4*13);
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@ -305,7 +316,7 @@ static int metag_tls_set(struct task_struct *target,
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const void *kbuf, const void __user *ubuf)
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{
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int ret;
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void __user *tls;
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void __user *tls = target->thread.tls_ptr;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
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if (ret)
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@ -456,7 +456,8 @@ static int fpr_set(struct task_struct *target,
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&target->thread.fpu,
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0, sizeof(elf_fpregset_t));
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for (i = 0; i < NUM_FPU_REGS; i++) {
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BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t));
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for (i = 0; i < NUM_FPU_REGS && count >= sizeof(elf_fpreg_t); i++) {
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err = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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&fpr_val, i * sizeof(elf_fpreg_t),
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(i + 1) * sizeof(elf_fpreg_t));
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@ -351,7 +351,7 @@ static int genregs64_set(struct task_struct *target,
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}
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if (!ret) {
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unsigned long y;
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unsigned long y = regs->y;
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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&y,
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