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linux-kernel: [PATCH 2.4] CAP_FS_MASK: add CAP_LINUX_IMMUTABLE a

[PATCH 2.4] CAP_FS_MASK: add CAP_LINUX_IMMUTABLE and CAP_MKNOD

From: Serge E. Hallyn <serue_at_nospam>
Date: Wed Mar 25 2009 - 17:39:54 GMT
To: Willy Tarreau <w@1wt.eu>


When POSIX capabilities were introduced during the 2.1 Linux cycle, the fs mask, which represents the capabilities which having fsuid==0 is supposed to grant, did not include CAP_MKNOD and CAP_LINUX_IMMUTABLE. However, before capabilities the privilege to call these did in fact depend upon fsuid==0.

This patch introduces those capabilities into the fsmask, restoring the old behavior.

See the thread starting at http://lkml.org/lkml/2009/3/11/157 for reference.

Reported-by: Igor Zhbanov <izh1979@gmail.com> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: stable@kernel.org --- include/linux/capability.h | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff -Nrup linux-2.4.37/include/linux/capability.h linux-2.4.37.new/include/linux/capability.h --- linux-2.4.37/include/linux/capability.h 2008-12-02 02:01:34.000000000 -0600 +++ linux-2.4.37.new/include/linux/capability.h 2009-03-25 11:09:47.000000000 -0500 @@ -99,10 +99,6 @@ typedef __u32 kernel_cap_t;
#define CAP_FSETID 4
-/* Used to decide between falling back on the old suser() or fsuser(). */ - -#define CAP_FS_MASK 0x1f - /* Overrides the restriction that the real or effective user ID of a process sending a signal must match the real or effective user ID of the process receiving the signal. */ @@ -301,6 +297,16 @@ extern kernel_cap_t cap_bset;
#endif
+/* Used to decide between falling back on the old suser() or fsuser(). */ + +#define CAP_FS_MASK (CAP_TO_MASK(CAP_CHOWN) \ + | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ + | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ + | CAP_TO_MASK(CAP_FOWNER) \ + | CAP_TO_MASK(CAP_FSETID) \ + | CAP_TO_MASK(CAP_LINUX_IMMUTABLE) \ + | CAP_TO_MASK(CAP_MKNOD)) +
#define CAP_EMPTY_SET to_cap_t(0)
#define CAP_FULL_SET to_cap_t(~0)
#define CAP_INIT_EFF_SET to_cap_t(~0 & ~CAP_TO_MASK(CAP_SETPCAP))
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