| | 1 | /************************************************* |
| | 2 | * Exim - an Internet mail transport agent * |
| | 3 | *************************************************/ |
| | 4 | |
| | 5 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
| | 6 | /* See the file NOTICE for conditions of use and distribution. */ |
| | 7 | |
| | 8 | |
| | 9 | #include "../exim.h" |
| | 10 | #include "lf_functions.h" |
| | 11 | |
| | 12 | |
| | 13 | |
| | 14 | /************************************************* |
| | 15 | * Check a file's credentials * |
| | 16 | *************************************************/ |
| | 17 | |
| | 18 | /* fstat can normally be expected to work on an open file, but there are some |
| | 19 | NFS states where it may not. |
| | 20 | |
| | 21 | Arguments: |
| | 22 | fd an open file descriptor or -1 |
| | 23 | filename a file name if fd is -1 |
| | 24 | s_type type of file (S_IFREG or S_IFDIR) |
| | 25 | modemask a mask specifying mode bits that must *not* be set |
| | 26 | owners NULL or a list of of allowable uids, count in the first item |
| | 27 | owngroups NULL or a list of allowable gids, count in the first item |
| | 28 | type name of lookup type for putting in error message |
| | 29 | errmsg where to put an error message |
| | 30 | |
| | 31 | Returns: -1 stat() or fstat() failed |
| | 32 | 0 OK |
| | 33 | +1 something didn't match |
| | 34 | |
| | 35 | Side effect: sets errno to ERRNO_BADUGID, ERRNO_NOTREGULAR or ERRNO_BADMODE for |
| | 36 | bad uid/gid, not a regular file, or bad mode; otherwise leaves it |
| | 37 | to what fstat set it to. |
| | 38 | */ |
| | 39 | |
| | 40 | int |
| | 41 | lf_check_file(int fd, const uschar * filename, int s_type, int modemask, |
| | 42 | uid_t * owners, gid_t * owngroups, const char * type, uschar ** errmsg) |
| | 43 | { |
| | 44 | struct stat statbuf; |
| | 45 | |
| | 46 | if ((fd >= 0 && fstat(fd, &statbuf) != 0) || |
| | 47 | (fd < 0 && Ustat(filename, &statbuf) != 0)) |
| | 48 | { |
| | 49 | int save_errno = errno; |
| | 50 | *errmsg = string_sprintf("%s: stat failed", filename); |
| | 51 | errno = save_errno; |
| | 52 | return -1; |
| | 53 | } |
| | 54 | |
| | 55 | if ((statbuf.st_mode & S_IFMT) != s_type) |
| | 56 | { |
| | 57 | if (s_type == S_IFREG) |
| | 58 | { |
| | 59 | *errmsg = string_sprintf("%s is not a regular file (%s lookup)", |
| | 60 | filename, type); |
| | 61 | errno = ERRNO_NOTREGULAR; |
| | 62 | } |
| | 63 | else |
| | 64 | { |
| | 65 | *errmsg = string_sprintf("%s is not a directory (%s lookup)", |
| | 66 | filename, type); |
| | 67 | errno = ERRNO_NOTDIRECTORY; |
| | 68 | } |
| | 69 | return +1; |
| | 70 | } |
| | 71 | |
| | 72 | if ((statbuf.st_mode & modemask) != 0) |
| | 73 | { |
| | 74 | *errmsg = string_sprintf("%s (%s lookup): file mode %.4o should not contain " |
| | 75 | "%.4o", filename, type, statbuf.st_mode & 07777, |
| | 76 | statbuf.st_mode & modemask); |
| | 77 | errno = ERRNO_BADMODE; |
| | 78 | return +1; |
| | 79 | } |
| | 80 | |
| | 81 | if (owners != NULL) |
| | 82 | { |
| | 83 | BOOL uid_ok = FALSE; |
| | 84 | for (int i = 1; i <= (int)owners[0]; i++) |
| | 85 | if (owners[i] == statbuf.st_uid) { uid_ok = TRUE; break; } |
| | 86 | if (!uid_ok) |
| | 87 | { |
| | 88 | *errmsg = string_sprintf("%s (%s lookup): file has wrong owner", filename, |
| | 89 | type); |
| | 90 | errno = ERRNO_BADUGID; |
| | 91 | return +1; |
| | 92 | } |
| | 93 | } |
| | 94 | |
| | 95 | if (owngroups != NULL) |
| | 96 | { |
| | 97 | BOOL gid_ok = FALSE; |
| | 98 | for (int i = 1; i <= (int)owngroups[0]; i++) |
| | 99 | if (owngroups[i] == statbuf.st_gid) { gid_ok = TRUE; break; } |
| | 100 | if (!gid_ok) |
| | 101 | { |
| | 102 | *errmsg = string_sprintf("%s (%s lookup): file has wrong group", filename, |
| | 103 | type); |
| | 104 | errno = ERRNO_BADUGID; |
| | 105 | return +1; |
| | 106 | } |
| | 107 | } |
| | 108 | |
| | 109 | return 0; |
| | 110 | } |
| | 111 | |
| | 112 | /* End of lf_check_file.c */ |
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