* [PATCH bpf-next v2] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
@ 2022-07-31 18:10 Manu Bretelle
2022-08-01 12:18 ` Quentin Monnet
0 siblings, 1 reply; 4+ messages in thread
From: Manu Bretelle @ 2022-07-31 18:10 UTC (permalink / raw)
To: bpf, andrii, quentin
bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
fds.
Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
we can get the full program name from BTF.
This patch removes the restriction of name length when running `bpftool
prog show name ${name}`.
Test:
Tested against some internal program names that were longer than
`BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.
# previous behaviour
$ sudo bpftool prog show name some_long_program_name
Error: can't parse name
# with the patch
$ sudo ./bpftool prog show name some_long_program_name
123456789: tracing name some_long_program_name tag taghexa gpl ....
...
...
...
# too long
sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
Error: can't parse name
# not too long but no match
$ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')
Signed-off-by: Manu Bretelle <chantr4@gmail.com>
---
v1 -> v2:
* Fix commit message to follow patch submission guidelines
* use strncmp instead of strcmp
* reintroduce arg length check against MAX_PROG_FULL_NAME
tools/bpf/bpftool/common.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 067e9ea59e3b..3ea747b3b194 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
{
+ char prog_name[MAX_PROG_FULL_NAME];
unsigned int id = 0;
int fd, nb_fds = 0;
void *tmp;
@@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
goto err_close_fd;
}
- if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
- (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
+ if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
close(fd);
continue;
}
+ if (!tag) {
+ get_prog_full_name(&info, fd, prog_name,
+ sizeof(prog_name));
+ if (strncmp(nametag, prog_name, sizeof(prog_name))) {
+ close(fd);
+ continue;
+ }
+ }
+
if (nb_fds > 0) {
tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
if (!tmp) {
@@ -820,7 +829,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds)
NEXT_ARGP();
name = **argv;
- if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
+ if (strlen(name) > MAX_PROG_FULL_NAME - 1) {
p_err("can't parse name");
return -1;
}
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next v2] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
2022-07-31 18:10 [PATCH bpf-next v2] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name Manu Bretelle
@ 2022-08-01 12:18 ` Quentin Monnet
2022-08-01 12:39 ` Manu Bretelle
0 siblings, 1 reply; 4+ messages in thread
From: Quentin Monnet @ 2022-08-01 12:18 UTC (permalink / raw)
To: Manu Bretelle, bpf, andrii
On 31/07/2022 19:10, Manu Bretelle wrote:
> bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
> fds.
>
> Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
> we can get the full program name from BTF.
>
> This patch removes the restriction of name length when running `bpftool
> prog show name ${name}`.
>
> Test:
> Tested against some internal program names that were longer than
> `BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.
>
> # previous behaviour
> $ sudo bpftool prog show name some_long_program_name
> Error: can't parse name
> # with the patch
> $ sudo ./bpftool prog show name some_long_program_name
> 123456789: tracing name some_long_program_name tag taghexa gpl ....
> ...
> ...
> ...
> # too long
> sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
> Error: can't parse name
> # not too long but no match
> $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')
>
> Signed-off-by: Manu Bretelle <chantr4@gmail.com>
>
> ---
>
> v1 -> v2:
> * Fix commit message to follow patch submission guidelines
> * use strncmp instead of strcmp
> * reintroduce arg length check against MAX_PROG_FULL_NAME
>
>
> tools/bpf/bpftool/common.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> index 067e9ea59e3b..3ea747b3b194 100644
> --- a/tools/bpf/bpftool/common.c
> +++ b/tools/bpf/bpftool/common.c
> @@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
>
> static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
> {
> + char prog_name[MAX_PROG_FULL_NAME];
> unsigned int id = 0;
> int fd, nb_fds = 0;
> void *tmp;
> @@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
> goto err_close_fd;
> }
>
> - if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
> - (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
> + if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
> close(fd);
> continue;
> }
>
> + if (!tag) {
> + get_prog_full_name(&info, fd, prog_name,
> + sizeof(prog_name));
Nit: This line should be aligned with the opening parenthesis from the
line above, checkpatch.pl complains about it. Probably not worth sending
a new version just for that, though.
> + if (strncmp(nametag, prog_name, sizeof(prog_name))) {
> + close(fd);
> + continue;
> + }
> + }
> +
> if (nb_fds > 0) {
> tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
> if (!tmp) {
> @@ -820,7 +829,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds)
> NEXT_ARGP();
>
> name = **argv;
> - if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
> + if (strlen(name) > MAX_PROG_FULL_NAME - 1) {
> p_err("can't parse name");
> return -1;
> }
Looks good, thank you!
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next v2] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
2022-08-01 12:18 ` Quentin Monnet
@ 2022-08-01 12:39 ` Manu Bretelle
2022-08-01 12:52 ` Quentin Monnet
0 siblings, 1 reply; 4+ messages in thread
From: Manu Bretelle @ 2022-08-01 12:39 UTC (permalink / raw)
To: Quentin Monnet; +Cc: bpf, andrii
On Mon, Aug 1, 2022 at 5:18 AM Quentin Monnet <quentin@isovalent.com> wrote:
>
> On 31/07/2022 19:10, Manu Bretelle wrote:
> > bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
> > fds.
> >
> > Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
> > we can get the full program name from BTF.
> >
> > This patch removes the restriction of name length when running `bpftool
> > prog show name ${name}`.
> >
> > Test:
> > Tested against some internal program names that were longer than
> > `BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.
> >
> > # previous behaviour
> > $ sudo bpftool prog show name some_long_program_name
> > Error: can't parse name
> > # with the patch
> > $ sudo ./bpftool prog show name some_long_program_name
> > 123456789: tracing name some_long_program_name tag taghexa gpl ....
> > ...
> > ...
> > ...
> > # too long
> > sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
> > Error: can't parse name
> > # not too long but no match
> > $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')
> >
> > Signed-off-by: Manu Bretelle <chantr4@gmail.com>
> >
> > ---
> >
> > v1 -> v2:
> > * Fix commit message to follow patch submission guidelines
> > * use strncmp instead of strcmp
> > * reintroduce arg length check against MAX_PROG_FULL_NAME
> >
> >
> > tools/bpf/bpftool/common.c | 15 ++++++++++++---
> > 1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> > index 067e9ea59e3b..3ea747b3b194 100644
> > --- a/tools/bpf/bpftool/common.c
> > +++ b/tools/bpf/bpftool/common.c
> > @@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
> >
> > static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
> > {
> > + char prog_name[MAX_PROG_FULL_NAME];
> > unsigned int id = 0;
> > int fd, nb_fds = 0;
> > void *tmp;
> > @@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
> > goto err_close_fd;
> > }
> >
> > - if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
> > - (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
> > + if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
> > close(fd);
> > continue;
> > }
> >
> > + if (!tag) {
> > + get_prog_full_name(&info, fd, prog_name,
> > + sizeof(prog_name));
>
> Nit: This line should be aligned with the opening parenthesis from the
> line above, checkpatch.pl complains about it. Probably not worth sending
> a new version just for that, though.
Yeah, I saw that on patchwork. For some reason, the `checkpatch.pl`
version I had from bpf-next tree did not catch this.
Originally, I was getting an error because it was more than 75 char
long. Eventually found out that shiftwidth should have been set to 8
(mine was 4).
I am happy to provide a corrected version if you want, this is really
just a matter of a minute now that I have the right vim indentation
setting.
>
> > + if (strncmp(nametag, prog_name, sizeof(prog_name))) {
> > + close(fd);
> > + continue;
> > + }
> > + }
> > +
> > if (nb_fds > 0) {
> > tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
> > if (!tmp) {
> > @@ -820,7 +829,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds)
> > NEXT_ARGP();
> >
> > name = **argv;
> > - if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
> > + if (strlen(name) > MAX_PROG_FULL_NAME - 1) {
> > p_err("can't parse name");
> > return -1;
> > }
>
> Looks good, thank you!
>
> Reviewed-by: Quentin Monnet <quentin@isovalent.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next v2] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
2022-08-01 12:39 ` Manu Bretelle
@ 2022-08-01 12:52 ` Quentin Monnet
0 siblings, 0 replies; 4+ messages in thread
From: Quentin Monnet @ 2022-08-01 12:52 UTC (permalink / raw)
To: Manu Bretelle; +Cc: bpf, andrii
On 01/08/2022 13:39, Manu Bretelle wrote:
> On Mon, Aug 1, 2022 at 5:18 AM Quentin Monnet <quentin@isovalent.com> wrote:
>>
>> On 31/07/2022 19:10, Manu Bretelle wrote:
>>> bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
>>> fds.
>>>
>>> Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
>>> we can get the full program name from BTF.
>>>
>>> This patch removes the restriction of name length when running `bpftool
>>> prog show name ${name}`.
>>>
>>> Test:
>>> Tested against some internal program names that were longer than
>>> `BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.
>>>
>>> # previous behaviour
>>> $ sudo bpftool prog show name some_long_program_name
>>> Error: can't parse name
>>> # with the patch
>>> $ sudo ./bpftool prog show name some_long_program_name
>>> 123456789: tracing name some_long_program_name tag taghexa gpl ....
>>> ...
>>> ...
>>> ...
>>> # too long
>>> sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
>>> Error: can't parse name
>>> # not too long but no match
>>> $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')
>>>
>>> Signed-off-by: Manu Bretelle <chantr4@gmail.com>
>>>
>>> ---
>>>
>>> v1 -> v2:
>>> * Fix commit message to follow patch submission guidelines
>>> * use strncmp instead of strcmp
>>> * reintroduce arg length check against MAX_PROG_FULL_NAME
>>>
>>>
>>> tools/bpf/bpftool/common.c | 15 ++++++++++++---
>>> 1 file changed, 12 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
>>> index 067e9ea59e3b..3ea747b3b194 100644
>>> --- a/tools/bpf/bpftool/common.c
>>> +++ b/tools/bpf/bpftool/common.c
>>> @@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
>>>
>>> static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
>>> {
>>> + char prog_name[MAX_PROG_FULL_NAME];
>>> unsigned int id = 0;
>>> int fd, nb_fds = 0;
>>> void *tmp;
>>> @@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
>>> goto err_close_fd;
>>> }
>>>
>>> - if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
>>> - (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
>>> + if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
>>> close(fd);
>>> continue;
>>> }
>>>
>>> + if (!tag) {
>>> + get_prog_full_name(&info, fd, prog_name,
>>> + sizeof(prog_name));
>>
>> Nit: This line should be aligned with the opening parenthesis from the
>> line above, checkpatch.pl complains about it. Probably not worth sending
>> a new version just for that, though.
>
> Yeah, I saw that on patchwork. For some reason, the `checkpatch.pl`
> version I had from bpf-next tree did not catch this.
It's because it's a low-level issue: a “check” for checkpatch, not a
“warning” or an “error”. Checkpatch will only report this if you run it
with "--strict", which the CI does.
> Originally, I was getting an error because it was more than 75 char
> long. Eventually found out that shiftwidth should have been set to 8
> (mine was 4).
> I am happy to provide a corrected version if you want, this is really
> just a matter of a minute now that I have the right vim indentation
> setting.
OK let's do this. Please keep my Reviewed-by on v3.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-07-31 18:10 [PATCH bpf-next v2] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name Manu Bretelle
2022-08-01 12:18 ` Quentin Monnet
2022-08-01 12:39 ` Manu Bretelle
2022-08-01 12:52 ` Quentin Monnet
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