From ca05a99a54db1db5bca72eccb5866d2a86f8517f Mon Sep 17 00:00:00 2001 From: "Andrew G. Morgan" Date: Tue, 27 May 2008 22:05:17 -0700 Subject: capabilities: remain source compatible with 32-bit raw legacy capability support. Source code out there hard-codes a notion of what the _LINUX_CAPABILITY_VERSION #define means in terms of the semantics of the raw capability system calls capget() and capset(). Its unfortunate, but true. Since the confusing header file has been in a released kernel, there is software that is erroneously using 64-bit capabilities with the semantics of 32-bit compatibilities. These recently compiled programs may suffer corruption of their memory when sys_getcap() overwrites more memory than they are coded to expect, and the raising of added capabilities when using sys_capset(). As such, this patch does a number of things to clean up the situation for all. It 1. forces the _LINUX_CAPABILITY_VERSION define to always retain its legacy value. 2. adopts a new #define strategy for the kernel's internal implementation of the preferred magic. 3. deprecates v2 capability magic in favor of a new (v3) magic number. The functionality of v3 is entirely equivalent to v2, the only difference being that the v2 magic causes the kernel to log a "deprecated" warning so the admin can find applications that may be using v2 inappropriately. [User space code continues to be encouraged to use the libcap API which protects the application from details like this. libcap-2.10 is the first to support v3 capabilities.] Fixes issue reported in https://bugzilla.redhat.com/show_bug.cgi?id=447518. Thanks to Bojan Smojver for the report. [akpm@linux-foundation.org: s/depreciate/deprecate/g] [akpm@linux-foundation.org: be robust about put_user size] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew G. Morgan Cc: Serge E. Hallyn Cc: Bojan Smojver Cc: stable@kernel.org Signed-off-by: Andrew Morton Signed-off-by: Chris Wright --- include/linux/capability.h | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) (limited to 'include/linux/capability.h') diff --git a/include/linux/capability.h b/include/linux/capability.h index f4ea0dd9a618..fa830f8de032 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -31,11 +31,11 @@ struct task_struct; #define _LINUX_CAPABILITY_VERSION_1 0x19980330 #define _LINUX_CAPABILITY_U32S_1 1 -#define _LINUX_CAPABILITY_VERSION_2 0x20071026 +#define _LINUX_CAPABILITY_VERSION_2 0x20071026 /* deprecated - use v3 */ #define _LINUX_CAPABILITY_U32S_2 2 -#define _LINUX_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_2 -#define _LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_2 +#define _LINUX_CAPABILITY_VERSION_3 0x20080522 +#define _LINUX_CAPABILITY_U32S_3 2 typedef struct __user_cap_header_struct { __u32 version; @@ -77,10 +77,23 @@ struct vfs_cap_data { } data[VFS_CAP_U32]; }; -#ifdef __KERNEL__ +#ifndef __KERNEL__ + +/* + * Backwardly compatible definition for source code - trapped in a + * 32-bit world. If you find you need this, please consider using + * libcap to untrap yourself... + */ +#define _LINUX_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_1 +#define _LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_1 + +#else + +#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3 +#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 typedef struct kernel_cap_struct { - __u32 cap[_LINUX_CAPABILITY_U32S]; + __u32 cap[_KERNEL_CAPABILITY_U32S]; } kernel_cap_t; #define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct)) @@ -351,7 +364,7 @@ typedef struct kernel_cap_struct { */ #define CAP_FOR_EACH_U32(__capi) \ - for (__capi = 0; __capi < _LINUX_CAPABILITY_U32S; ++__capi) + for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ @@ -361,7 +374,7 @@ typedef struct kernel_cap_struct { # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) -#if _LINUX_CAPABILITY_U32S != 2 +#if _KERNEL_CAPABILITY_U32S != 2 # error Fix up hand-coded capability macro initializers #else /* HAND-CODED capability initializers */ @@ -372,7 +385,7 @@ typedef struct kernel_cap_struct { # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0|CAP_TO_MASK(CAP_SYS_RESOURCE), \ CAP_FS_MASK_B1 } }) -#endif /* _LINUX_CAPABILITY_U32S != 2 */ +#endif /* _KERNEL_CAPABILITY_U32S != 2 */ #define CAP_INIT_INH_SET CAP_EMPTY_SET -- cgit v1.2.3 From 086f7316f0d400806d76323beefae996bb3849b1 Mon Sep 17 00:00:00 2001 From: "Andrew G. Morgan" Date: Fri, 4 Jul 2008 09:59:58 -0700 Subject: security: filesystem capabilities: fix fragile setuid fixup code This commit includes a bugfix for the fragile setuid fixup code in the case that filesystem capabilities are supported (in access()). The effect of this fix is gated on filesystem capability support because changing securebits is only supported when filesystem capabilities support is configured.) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew G. Morgan Acked-by: Serge Hallyn Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/capability.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/capability.h') diff --git a/include/linux/capability.h b/include/linux/capability.h index fa830f8de032..02673846d205 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -501,6 +501,8 @@ extern const kernel_cap_t __cap_empty_set; extern const kernel_cap_t __cap_full_set; extern const kernel_cap_t __cap_init_eff_set; +kernel_cap_t cap_set_effective(const kernel_cap_t pE_new); + int capable(int cap); int __capable(struct task_struct *t, int cap); -- cgit v1.2.3