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authorRusty Russell <rusty@rustcorp.com.au>2014-03-24 12:00:34 +1030
committerRusty Russell <rusty@rustcorp.com.au>2014-03-24 12:21:00 +1030
commit58f86cc89c3372d3e61d5b71e5513ec5a0b02848 (patch)
treeba12cb68846c5e4e04d3442528dee70e58100859 /include/linux/kernel.h
parentc6bda7c988a57958108741cde9b1f12e9727a938 (diff)
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VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.
Summary of http://lkml.org/lkml/2014/3/14/363 : Ted: module_param(queue_depth, int, 444) Joe: 0444! Rusty: User perms >= group perms >= other perms? Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2? Side effect of stricter permissions means removing the unnecessary S_IFREG from several callers. Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair number of drivers fail this test, so that will be the debate for a future patch. Suggested-by: Joe Perches <joe@perches.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> for drivers/pci/slot.c Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'include/linux/kernel.h')
-rw-r--r--include/linux/kernel.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 471090093c67..4679eddc110a 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -842,4 +842,12 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
#endif
+/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
+#define VERIFY_OCTAL_PERMISSIONS(perms) \
+ (BUILD_BUG_ON_ZERO((perms) < 0) + \
+ BUILD_BUG_ON_ZERO((perms) > 0777) + \
+ /* User perms >= group perms >= other perms */ \
+ BUILD_BUG_ON_ZERO(((perms) >> 6) < (((perms) >> 3) & 7)) + \
+ BUILD_BUG_ON_ZERO((((perms) >> 3) & 7) < ((perms) & 7)) + \
+ (perms))
#endif