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authorRichard Weinberger <richard@nod.at>2017-04-01 00:41:57 +0200
committerRichard Weinberger <richard@nod.at>2017-05-03 22:35:31 +0200
commit9abc74a22d85ab29cef9896a2582a530da7e79bf (patch)
tree635cd7bee778f32723b10fdfaf8df73da7ba3245 /arch/x86/um
parent8bba077066d6d0a135b7be1970691522075bf905 (diff)
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.c2
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;