linux/kernel/events
Oleg Nesterov 2ded0980a6 uprobes: Fix the memory out of bound overwrite in copy_insn()
1. copy_insn() doesn't look very nice, all calculations are
   confusing and it is not immediately clear why do we read
   the 2nd page first.

2. The usage of inode->i_size is wrong on 32-bit machines.

3. "Instruction at end of binary" logic is simply wrong, it
   doesn't handle the case when uprobe->offset > inode->i_size.

   In this case "bytes" overflows, and __copy_insn() writes to
   the memory outside of uprobe->arch.insn.

   Yes, uprobe_register() checks i_size_read(), but this file
   can be truncated after that. All i_size checks are racy, we
   do this only to catch the obvious mistakes.

Change copy_insn() to call __copy_insn() in a loop, simplify
and fix the bytes/nbytes calculations.

Note: we do not care if we read extra bytes after inode->i_size
if we got the valid page. This is fine because the task gets the
same page after page-fault, and arch_uprobe_analyze_insn() can't
know how many bytes were actually read anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-11-09 17:05:43 +01:00
..
Makefile uprobes: Move to kernel/events/ 2012-02-22 11:08:00 +01:00
callchain.c perf: Roll back callchain buffer refcount under the callchain mutex 2013-08-16 17:55:50 +02:00
core.c perf: Factor out strncpy() in perf_event_mmap_event() 2013-11-06 12:34:28 +01:00
hw_breakpoint.c hw_breakpoint: Introduce "struct bp_cpuinfo" 2013-06-20 17:58:57 +02:00
internal.h perf: Fix arch_perf_out_copy_user default 2013-11-06 12:34:25 +01:00
ring_buffer.c perf: Update a stale comment 2013-11-06 12:34:23 +01:00
uprobes.c uprobes: Fix the memory out of bound overwrite in copy_insn() 2013-11-09 17:05:43 +01:00