Jann Horn 8358b02bf6 bpf: fix double-fdput in replace_map_fd_with_map_ptr() ... When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode references a non-map file descriptor as a map file descriptor, the error handling code called fdput() twice instead of once (in __bpf_map_get() and in replace_map_fd_with_map_ptr()). If the file descriptor table of the current task is shared, this causes f_count to be decremented too much, allowing the struct file to be freed while it is still in use (use-after-free). This can be exploited to gain root privileges by an unprivileged user. This bug was introduced in commit 0246e64d9a ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only exploitable since commit 1be7f75d16 ("bpf: enable non-root eBPF programs") because previously, CAP_SYS_ADMIN was required to reach the vulnerable code. (posted publicly according to request by maintainer) Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>		2016-04-26 17:37:21 -04:00
..
Makefile	bpf: introduce percpu_freelist	2016-03-08 15:28:31 -05:00
arraymap.c	bpf: check for reserved flag bits in array and stack maps	2016-03-08 15:28:31 -05:00
core.c	bpf: Mark __bpf_prog_run() stack frame as non-standard	2016-02-29 08:35:11 +01:00
hashtab.c	bpf: pre-allocate hash map elements	2016-03-08 15:28:31 -05:00
helpers.c	bpf: avoid copying junk bytes in bpf_get_current_comm()	2016-03-09 23:27:30 -05:00
inode.c	bpf, inode: allow for rename and link ops	2015-12-12 18:44:23 -05:00
percpu_freelist.c	bpf: introduce percpu_freelist	2016-03-08 15:28:31 -05:00
percpu_freelist.h	bpf: introduce percpu_freelist	2016-03-08 15:28:31 -05:00
stackmap.c	bpf: convert stackmap to pre-allocation	2016-03-08 15:28:31 -05:00
syscall.c	bpf: add missing map_flags to bpf_map_show_fdinfo	2016-03-25 11:36:41 -04:00
verifier.c	bpf: fix double-fdput in replace_map_fd_with_map_ptr()	2016-04-26 17:37:21 -04:00