bpf: fix checking xdp_adjust_head on tail calls
Commit17bedab272
("bpf: xdp: Allow head adjustment in XDP prog") added the xdp_adjust_head bit to the BPF prog in order to tell drivers that the program that is to be attached requires support for the XDP bpf_xdp_adjust_head() helper such that drivers not supporting this helper can reject the program. There are also drivers that do support the helper, but need to check for xdp_adjust_head bit in order to move packet metadata prepended by the firmware away for making headroom. For these cases, the current check for xdp_adjust_head bit is insufficient since there can be cases where the program itself does not use the bpf_xdp_adjust_head() helper, but tail calls into another program that uses bpf_xdp_adjust_head(). As such, the xdp_adjust_head bit is still set to 0. Since the first program has no control over which program it calls into, we need to assume that bpf_xdp_adjust_head() helper is used upon tail calls. Thus, for the very same reasons in cb_access, set the xdp_adjust_head bit to 1 when the main program uses tail calls. Fixes:17bedab272
("bpf: xdp: Allow head adjustment in XDP prog") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
6b1bb01bcc
commit
c2002f9837
|
@ -623,6 +623,7 @@ static void fixup_bpf_calls(struct bpf_prog *prog)
|
|||
* in the program array.
|
||||
*/
|
||||
prog->cb_access = 1;
|
||||
prog->xdp_adjust_head = 1;
|
||||
|
||||
/* mark bpf_tail_call as different opcode
|
||||
* to avoid conditional branch in
|
||||
|
|
Loading…
Reference in a new issue