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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | #ifndef _LINUX_HIGHUID_H |
| 2 | #define _LINUX_HIGHUID_H |
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| 3 | |||
| 4 | #include <linux/config.h> |
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| 5 | #include <linux/types.h> |
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| 6 | |||
| 7 | /* |
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| 8 | * general notes: |
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| 9 | * |
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| 10 | * CONFIG_UID16 is defined if the given architecture needs to |
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| 11 | * support backwards compatibility for old system calls. |
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| 12 | * |
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| 13 | * kernel code should use uid_t and gid_t at all times when dealing with |
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| 14 | * kernel-private data. |
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| 15 | * |
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| 16 | * old_uid_t and old_gid_t should only be different if CONFIG_UID16 is |
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| 17 | * defined, else the platform should provide dummy typedefs for them |
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| 18 | * such that they are equivalent to __kernel_{u,g}id_t. |
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| 19 | * |
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| 20 | * uid16_t and gid16_t are used on all architectures. (when dealing |
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| 21 | * with structures hard coded to 16 bits, such as in filesystems) |
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| 22 | */ |
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| 23 | |||
| 24 | |||
| 25 | /* |
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| 26 | * This is the "overflow" UID and GID. They are used to signify uid/gid |
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| 27 | * overflow to old programs when they request uid/gid information but are |
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| 28 | * using the old 16 bit interfaces. |
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| 29 | * When you run a libc5 program, it will think that all highuid files or |
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| 30 | * processes are owned by this uid/gid. |
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| 31 | * The idea is that it's better to do so than possibly return 0 in lieu of |
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| 32 | * 65536, etc. |
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| 33 | */ |
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| 34 | |||
| 35 | extern int overflowuid; |
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| 36 | extern int overflowgid; |
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| 37 | |||
| 38 | extern void __bad_uid(void); |
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| 39 | extern void __bad_gid(void); |
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| 40 | |||
| 41 | #define DEFAULT_OVERFLOWUID 65534 |
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| 42 | #define DEFAULT_OVERFLOWGID 65534 |
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| 43 | |||
| 44 | #ifdef CONFIG_UID16 |
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| 45 | |||
| 46 | /* prevent uid mod 65536 effect by returning a default value for high UIDs */ |
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| 47 | #define high2lowuid(uid) ((uid) > 65535 ? (old_uid_t)overflowuid : (old_uid_t)(uid)) |
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| 48 | #define high2lowgid(gid) ((gid) > 65535 ? (old_gid_t)overflowgid : (old_gid_t)(gid)) |
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| 49 | /* |
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| 50 | * -1 is different in 16 bits than it is in 32 bits |
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| 51 | * these macros are used by chown(), setreuid(), ..., |
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| 52 | */ |
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| 53 | #define low2highuid(uid) ((uid) == (old_uid_t)-1 ? (uid_t)-1 : (uid_t)(uid)) |
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| 54 | #define low2highgid(gid) ((gid) == (old_gid_t)-1 ? (gid_t)-1 : (gid_t)(gid)) |
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| 55 | |||
| 56 | #define __convert_uid(size, uid) \ |
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| 57 | (size >= sizeof(uid) ? (uid) : high2lowuid(uid)) |
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| 58 | #define __convert_gid(size, gid) \ |
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| 59 | (size >= sizeof(gid) ? (gid) : high2lowgid(gid)) |
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| 60 | |||
| 61 | |||
| 62 | #else |
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| 63 | |||
| 64 | #define __convert_uid(size, uid) (uid) |
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| 65 | #define __convert_gid(size, gid) (gid) |
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| 66 | |||
| 67 | #endif /* !CONFIG_UID16 */ |
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| 68 | |||
| 69 | /* uid/gid input should be always 32bit uid_t */ |
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| 70 | #define SET_UID(var, uid) do { (var) = __convert_uid(sizeof(var), (uid)); } while (0) |
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| 71 | #define SET_GID(var, gid) do { (var) = __convert_gid(sizeof(var), (gid)); } while (0) |
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| 72 | |||
| 73 | /* |
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| 74 | * Everything below this line is needed on all architectures, to deal with |
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| 75 | * filesystems that only store 16 bits of the UID/GID, etc. |
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| 76 | */ |
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| 77 | |||
| 78 | /* |
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| 79 | * This is the UID and GID that will get written to disk if a filesystem |
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| 80 | * only supports 16-bit UIDs and the kernel has a high UID/GID to write |
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| 81 | */ |
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| 82 | extern int fs_overflowuid; |
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| 83 | extern int fs_overflowgid; |
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| 84 | |||
| 85 | #define DEFAULT_FS_OVERFLOWUID 65534 |
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| 86 | #define DEFAULT_FS_OVERFLOWGID 65534 |
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| 87 | |||
| 88 | /* |
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| 89 | * Since these macros are used in architectures that only need limited |
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| 90 | * 16-bit UID back compatibility, we won't use old_uid_t and old_gid_t |
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| 91 | */ |
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| 92 | #define fs_high2lowuid(uid) ((uid) > 65535 ? (uid16_t)fs_overflowuid : (uid16_t)(uid)) |
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| 93 | #define fs_high2lowgid(gid) ((gid) > 65535 ? (gid16_t)fs_overflowgid : (gid16_t)(gid)) |
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| 94 | |||
| 95 | #define low_16_bits(x) ((x) & 0xFFFF) |
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| 96 | #define high_16_bits(x) (((x) & 0xFFFF0000) >> 16) |
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| 97 | |||
| 98 | #endif /* _LINUX_HIGHUID_H */ |