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| author | Richard Weinberger <richard@nod.at> | 2017-04-01 01:41:57 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-08-26 04:14:05 +0300 |
| commit | c58b2c46505568ac70aadffc338a7a90272c6d4b (patch) | |
| tree | 1e7e5c4e11e248b6f2b1b9437fefef80e2c6a0ab /arch | |
| parent | c5de619ea4ec388a580426d9bbd5e29fed5cd0b3 (diff) | |
| download | linux-c58b2c46505568ac70aadffc338a7a90272c6d4b.tar.xz | |
um: Fix PTRACE_POKEUSER on x86_64
commit 9abc74a22d85ab29cef9896a2582a530da7e79bf upstream.
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.
Reported-by: jie cao <cj3054@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -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 3b52bf0b418a..b0d25e6ef464 100644 --- a/arch/x86/um/ptrace_64.c +++ b/arch/x86/um/ptrace_64.c @@ -120,7 +120,7 @@ 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; |