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| author | Richard Weinberger <richard@nod.at> | 2017-04-01 00:41:57 +0200 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2017-05-03 22:35:31 +0200 |
| commit | 9abc74a22d85ab29cef9896a2582a530da7e79bf (patch) | |
| tree | 635cd7bee778f32723b10fdfaf8df73da7ba3245 /arch/x86/um | |
| parent | 8bba077066d6d0a135b7be1970691522075bf905 (diff) | |
| download | lwn-9abc74a22d85ab29cef9896a2582a530da7e79bf.tar.gz lwn-9abc74a22d85ab29cef9896a2582a530da7e79bf.zip | |
um: Fix PTRACE_POKEUSER on x86_64
This is broken since ever but sadly nobody noticed.
Recent versions of GDB set DR_CONTROL unconditionally and
UML dies due to a heap corruption. It turns out that
the PTRACE_POKEUSER was copy&pasted from i386 and assumes
that addresses are 4 bytes long.
Fix that by using 8 as address size in the calculation.
Cc: <stable@vger.kernel.org>
Reported-by: jie cao <cj3054@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/x86/um')
| -rw-r--r-- | arch/x86/um/ptrace_64.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c index a5c9910d234f..09a085bde0d4 100644 --- a/arch/x86/um/ptrace_64.c +++ b/arch/x86/um/ptrace_64.c @@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, long addr, long data) else if ((addr >= offsetof(struct user, u_debugreg[0])) && (addr <= offsetof(struct user, u_debugreg[7]))) { addr -= offsetof(struct user, u_debugreg[0]); - addr = addr >> 2; + addr = addr >> 3; if ((addr == 4) || (addr == 5)) return -EIO; child->thread.arch.debugregs[addr] = data; |