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[bpf,v3] libbpf: sanitise map names before pinning

Message ID 20201203093306.107676-1-toke@redhat.com (mailing list archive)
State Accepted
Commit 9cf309c56f7910a81fbe053b6f11c3b1f0987b12
Delegated to: BPF
Headers show
Series [bpf,v3] libbpf: sanitise map names before pinning | expand

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netdev/cover_letter success Link
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netdev/source_inline success Was 0 now: 0
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netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
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netdev/verify_fixes success Link
netdev/checkpatch warning WARNING: From:/Signed-off-by: email name mismatch: 'From: "Toke Høiland-Jørgensen" <toke@redhat.com>' != 'Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>'
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
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netdev/stable success Stable not CCed

Commit Message

Toke Høiland-Jørgensen Dec. 3, 2020, 9:33 a.m. UTC
When we added sanitising of map names before loading programs to libbpf, we
still allowed periods in the name. While the kernel will accept these for
the map names themselves, they are not allowed in file names when pinning
maps. This means that bpf_object__pin_maps() will fail if called on an
object that contains internal maps (such as sections .rodata).

Fix this by replacing periods with underscores when constructing map pin
paths. This only affects the paths generated by libbpf when
bpf_object__ping_maps() is called with a path argument. Any pin paths set
by bpf_map__set_pin_path() are unaffected, and it will still be up to the
caller to avoid invalid characters in those.

Fixes: 113e6b7e15e2 ("libbpf: Sanitise internal map names so they are not rejected by the kernel")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
v3:
  - void return for helper function
v2:
  - Move string munging to helper function

 tools/lib/bpf/libbpf.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Comments

patchwork-bot+netdevbpf@kernel.org Dec. 3, 2020, 8:10 p.m. UTC | #1
Hello:

This patch was applied to bpf/bpf-next.git (refs/heads/master):

On Thu,  3 Dec 2020 10:33:06 +0100 you wrote:
> When we added sanitising of map names before loading programs to libbpf, we
> still allowed periods in the name. While the kernel will accept these for
> the map names themselves, they are not allowed in file names when pinning
> maps. This means that bpf_object__pin_maps() will fail if called on an
> object that contains internal maps (such as sections .rodata).
> 
> Fix this by replacing periods with underscores when constructing map pin
> paths. This only affects the paths generated by libbpf when
> bpf_object__ping_maps() is called with a path argument. Any pin paths set
> by bpf_map__set_pin_path() are unaffected, and it will still be up to the
> caller to avoid invalid characters in those.
> 
> [...]

Here is the summary with links:
  - [bpf,v3] libbpf: sanitise map names before pinning
    https://git.kernel.org/bpf/bpf-next/c/9cf309c56f79

You are awesome, thank you!
--
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diff mbox series

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8d05132e1945..4a933ae64297 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7651,6 +7651,16 @@  bool bpf_map__is_pinned(const struct bpf_map *map)
 	return map->pinned;
 }
 
+static void sanitize_pin_path(char *s)
+{
+	/* bpffs disallows periods in path names */
+	while (*s) {
+		if (*s == '.')
+			*s = '_';
+		s++;
+	}
+}
+
 int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
 {
 	struct bpf_map *map;
@@ -7680,6 +7690,7 @@  int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
 				err = -ENAMETOOLONG;
 				goto err_unpin_maps;
 			}
+			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
 			continue;
@@ -7724,6 +7735,7 @@  int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 				return -EINVAL;
 			else if (len >= PATH_MAX)
 				return -ENAMETOOLONG;
+			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
 			continue;