Re: [PATCH bpf v3] x86/cpufeature: bpf hack for clang not supporting asm goto

On Thu, May 10, 2018 at 9:28 AM Borislav Petkov wrote: > As someone already pointed out on IRC, arch/x86/include/asm/cpufeature.h > is solely a kernel header so nothing but kernel should include it. So > forget the userspace breakage "argument". For what is worth, I have the same exact problem

Re: [RFC bpf] bpf, x64: fix JIT emission for dead code

On Wed, Apr 25, 2018 at 8:34 AM Daniel Borkmann wrote: > I've applied this fix to bpf tree, thanks Gianluca! Thank you all for the quick review, really appreciated!

[RFC bpf] bpf, x64: fix JIT emission for dead code

be safely translated into a 0xEB instruction with a jump offset of -2. Such fix brings the BPF program in the previous example to complete again in ~9 passes. Fixes: 2a5418a13fcf ("bpf: improve dead code sanitizing") Signed-off-by: Gianluca Borello --- Hi Posting this as RFC since I

Re: Issue accessing task_struct from BPF due to 4.16 stack-protector changes

On Fri, Mar 2, 2018 at 12:42 PM, Alexei Starovoitov wrote: > > good catch! > I wonder why sched.h is using this flag insead of relying on #defines from > autoconf.h > It could have been using CONFIG_HAVE_CC_STACKPROTECTOR > instead of CONFIG_CC_STACKPROTECTOR, no ? > Thanks for your reply Alexei

Issue accessing task_struct from BPF due to 4.16 stack-protector changes

Hello, While testing bpf-next, I noticed that I was reading garbage when accessing some task_struct members, and the issue seems caused by the recent commit 2bc2f688fdf8 ("Makefile: move stack-protector availability out of Kconfig") which removes CONFIG_CC_STACKPROTECTOR from autoconf.h. When I c

[PATCH bpf-next] bpf: fix stacksafe exploration when comparing states

first test, without this fix instructions 16 and 17 are replaced with nops instead of being rejected by the verifier. The second test, instead, allows a program to make a potentially illegal read from the stack. Fixes: cc2b14d51053 ("bpf: teach verifier to recognize zero initialized stack&quo

Re: len = bpf_probe_read_str(); bpf_perf_event_output(... len) == FAIL

On Tue, Nov 21, 2017 at 2:31 PM, Alexei Starovoitov wrote: > > yeah sorry about this hack. Gianluca reported this issue as well. > Yonghong fixed it for bpf_probe_read only. We will extend > the fix to bpf_probe_read_str() and bpf_perf_event_output() asap. > The above workaround gets too much into

[PATCH net 3/4] bpf: change bpf_probe_read_str arg2 type to ARG_CONST_SIZE_OR_ZERO

ary since strncpy_from_unsafe itself immediately returns if the size passed is 0. Signed-off-by: Gianluca Borello Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- kernel/trace/bpf_trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/bpf_trace

[PATCH net 4/4] bpf: change bpf_perf_event_output arg5 type to ARG_CONST_SIZE_OR_ZERO

rf_event_output(ctx, &perf_map, 0, buf, len & 0x7fff); No changes to the bpf_perf_event_output helper are necessary since it can handle a case where size is 0, and an empty frame is pushed. Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Gianluca Borello Acked-by: Alexei Starovoitov

[PATCH net 2/4] bpf: remove explicit handling of 0 for arg2 in bpf_probe_read

bpf_probe_read arg2 type to ARG_CONST_SIZE_OR_ZERO") Signed-off-by: Gianluca Borello Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Acked-by: Yonghong Song --- kernel/trace/bpf_trace.c | 6 +- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/trace/bpf_tr

[PATCH net 1/4] bpf: introduce ARG_PTR_TO_MEM_OR_NULL

battery of tests that explicitly test the !ARG_PTR_TO_MEM_OR_NULL combination: all the current ones testing the various variations are focused on bpf_csum_diff, so cover also other helpers. Signed-off-by: Gianluca Borello Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- include/linux

[PATCH net 0/4] bpf: fix semantics issues with helpers receiving NULL arguments

for helpers that can receive a tuple. By doing so, we can fix the semantics of the other helpers that don't need and can just handle , allowing the code to get rid of those checks. Gianluca Borello (4): bpf: introduce ARG_PTR_TO_MEM_OR_NULL bpf: remove explicit handling of 0 for arg2 in bpf

[PATCH net-next] bpf: remove tail_call and get_stackid helper declarations from bpf.h

ic void (*bpf_tail_call)(void *ctx, void *map, int index); static int (*bpf_get_stackid)(void *ctx, void *map, int flags); Fix this by removing the unused declaration of bpf_tail_call and moving the declaration of bpf_get_stackid in bpf_trace.c, which is the only place where it's needed. Sig

[PATCH net-next] bpf: add bpf_probe_read_str helper

de changes simply leverage the already existent strncpy_from_unsafe() kernel function, which is safe to be called from a bpf program as it is used in bpf_trace_printk(). Signed-off-by: Gianluca Borello Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- include/uapi/linux/bpf.h | 15 +++