diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-29 08:55:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-29 08:55:25 -0700 |
| commit | 72c33734b5fa8a788734ad2312a89b944589c5a0 (patch) | |
| tree | f6e7aade79c95b3c655f288bc1745c1cf9750e2f /arch/metag | |
| parent | fe82203b63e598c34d96e846dea49679a726fc7a (diff) | |
| parent | d3805c546b275c8cc7d40f759d029ae92c7175f2 (diff) | |
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
Diffstat (limited to 'arch/metag')
| -rw-r--r-- | arch/metag/kernel/ptrace.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/arch/metag/kernel/ptrace.c b/arch/metag/kernel/ptrace.c index 5fd16ee5280c..e615603a4b0a 100644 --- a/arch/metag/kernel/ptrace.c +++ b/arch/metag/kernel/ptrace.c @@ -26,6 +26,16 @@ * user_regset definitions. */ +static unsigned long user_txstatus(const struct pt_regs *regs) +{ + unsigned long data = (unsigned long)regs->ctx.Flags; + + if (regs->ctx.SaveMask & TBICTX_CBUF_BIT) + data |= USER_GP_REGS_STATUS_CATCH_BIT; + + return data; +} + int metag_gp_regs_copyout(const struct pt_regs *regs, unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf) @@ -64,9 +74,7 @@ int metag_gp_regs_copyout(const struct pt_regs *regs, if (ret) goto out; /* TXSTATUS */ - data = (unsigned long)regs->ctx.Flags; - if (regs->ctx.SaveMask & TBICTX_CBUF_BIT) - data |= USER_GP_REGS_STATUS_CATCH_BIT; + data = user_txstatus(regs); ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &data, 4*25, 4*26); if (ret) @@ -121,6 +129,7 @@ int metag_gp_regs_copyin(struct pt_regs *regs, if (ret) goto out; /* TXSTATUS */ + data = user_txstatus(regs); ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &data, 4*25, 4*26); if (ret) @@ -246,6 +255,8 @@ int metag_rp_state_copyin(struct pt_regs *regs, unsigned long long *ptr; int ret, i; + if (count < 4*13) + return -EINVAL; /* Read the entire pipeline before making any changes */ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &rp, 0, 4*13); @@ -305,7 +316,7 @@ static int metag_tls_set(struct task_struct *target, const void *kbuf, const void __user *ubuf) { int ret; - void __user *tls; + void __user *tls = target->thread.tls_ptr; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1); if (ret) |