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| author | Andrew G. Morgan <morgan@kernel.org> | 2008-01-22 02:18:30 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-01-22 04:39:41 +0100 |
| commit | a6dbb1ef2fc8d73578eacd02ac701f4233175c9f (patch) | |
| tree | eb2efa0193cdc7ab6b1f30068571194d0dabf230 | |
| parent | s3c2410_fb: fix line length calculation (diff) | |
| download | linux-a6dbb1ef2fc8d73578eacd02ac701f4233175c9f.tar.xz linux-a6dbb1ef2fc8d73578eacd02ac701f4233175c9f.zip | |
Fix filesystem capability support
In linux-2.6.24-rc1, security/commoncap.c:cap_inh_is_capped() was
introduced. It has the exact reverse of its intended behavior. This
led to an unintended privilege esculation involving a process'
inheritable capability set.
To be exposed to this bug, you need to have Filesystem Capabilities
enabled and in use. That is:
- CONFIG_SECURITY_FILE_CAPABILITIES must be defined for the buggy code
to be compiled in.
- You also need to have files on your system marked with fI bits raised.
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@akpm@linux-foundation.org>
| -rw-r--r-- | security/commoncap.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index 5bc1895f3f9c..ea61bc73f6d3 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -59,6 +59,12 @@ int cap_netlink_recv(struct sk_buff *skb, int cap) EXPORT_SYMBOL(cap_netlink_recv); +/* + * NOTE WELL: cap_capable() cannot be used like the kernel's capable() + * function. That is, it has the reverse semantics: cap_capable() + * returns 0 when a task has a capability, but the kernel's capable() + * returns 1 for this case. + */ int cap_capable (struct task_struct *tsk, int cap) { /* Derived from include/linux/sched.h:capable. */ @@ -107,10 +113,11 @@ static inline int cap_block_setpcap(struct task_struct *target) static inline int cap_inh_is_capped(void) { /* - * return 1 if changes to the inheritable set are limited - * to the old permitted set. + * Return 1 if changes to the inheritable set are limited + * to the old permitted set. That is, if the current task + * does *not* possess the CAP_SETPCAP capability. */ - return !cap_capable(current, CAP_SETPCAP); + return (cap_capable(current, CAP_SETPCAP) != 0); } #else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */ |