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openSUSE:Leap:42.3:Staging:E
libarchive
CVE-2016-5418.patch
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File CVE-2016-5418.patch of Package libarchive
Index: libarchive-3.1.2/libarchive/archive_write_disk_posix.c =================================================================== --- libarchive-3.1.2.orig/libarchive/archive_write_disk_posix.c +++ libarchive-3.1.2/libarchive/archive_write_disk_posix.c @@ -326,12 +326,14 @@ struct archive_write_disk { #define HFS_BLOCKS(s) ((s) >> 12) +static int check_symlinks_fsobj(char *path, int *error_number, struct archive_string *error_string, int flags); static int check_symlinks(struct archive_write_disk *); static int create_filesystem_object(struct archive_write_disk *); static struct fixup_entry *current_fixup(struct archive_write_disk *, const char *pathname); #if defined(HAVE_FCHDIR) && defined(PATH_MAX) static void edit_deep_directories(struct archive_write_disk *ad); #endif +static int cleanup_pathname_fsobj(char *path, int *error_number, struct archive_string *error_string, int flags); static int cleanup_pathname(struct archive_write_disk *); static int create_dir(struct archive_write_disk *, char *); static int create_parent_dir(struct archive_write_disk *, char *); @@ -1791,7 +1793,7 @@ edit_deep_directories(struct archive_wri char *tail = a->name; /* If path is short, avoid the open() below. */ - if (strlen(tail) <= PATH_MAX) + if (strlen(tail) < PATH_MAX) return; /* Try to record our starting dir. */ @@ -1801,7 +1803,7 @@ edit_deep_directories(struct archive_wri return; /* As long as the path is too long... */ - while (strlen(tail) > PATH_MAX) { + while (strlen(tail) >= PATH_MAX) { /* Locate a dir prefix shorter than PATH_MAX. */ tail += PATH_MAX - 8; while (tail > a->name && *tail != '/') @@ -1996,6 +1998,10 @@ create_filesystem_object(struct archive_ const char *linkname; mode_t final_mode, mode; int r; + /* these for check_symlinks_fsobj */ + char *linkname_copy; /* non-const copy of linkname */ + struct archive_string error_string; + int error_number; /* We identify hard/symlinks according to the link names. */ /* Since link(2) and symlink(2) don't handle modes, we're done here. */ @@ -2004,6 +2010,27 @@ create_filesystem_object(struct archive_ #if !HAVE_LINK return (EPERM); #else + archive_string_init(&error_string); + linkname_copy = strdup(linkname); + if (linkname_copy == NULL) { + return (EPERM); + } + /* TODO: consider using the cleaned-up path as the link target? */ + r = cleanup_pathname_fsobj(linkname_copy, &error_number, &error_string, a->flags); + if (r != ARCHIVE_OK) { + archive_set_error(&a->archive, error_number, "%s", error_string.s); + free(linkname_copy); + /* EPERM is more appropriate than error_number for our callers */ + return (EPERM); + } + r = check_symlinks_fsobj(linkname_copy, &error_number, &error_string, a->flags); + if (r != ARCHIVE_OK) { + archive_set_error(&a->archive, error_number, "%s", error_string.s); + free(linkname_copy); + /* EPERM is more appropriate than error_number for our callers */ + return (EPERM); + } + free(linkname_copy); r = link(linkname, a->name) ? errno : 0; /* * New cpio and pax formats allow hardlink entries @@ -2343,99 +2370,215 @@ current_fixup(struct archive_write_disk * recent paths. */ /* TODO: Extend this to support symlinks on Windows Vista and later. */ + +/* + * Checks the given path to see if any elements along it are symlinks. Returns + * ARCHIVE_OK if there are none, otherwise puts an error in errmsg. + */ static int -check_symlinks(struct archive_write_disk *a) +check_symlinks_fsobj(char *path, int *error_number, struct archive_string *error_string, int flags) { #if !defined(HAVE_LSTAT) /* Platform doesn't have lstat, so we can't look for symlinks. */ - (void)a; /* UNUSED */ + (void)path; /* UNUSED */ + (void)error_number; /* UNUSED */ + (void)error_string; /* UNUSED */ + (void)flags; /* UNUSED */ return (ARCHIVE_OK); #else - char *pn; + int res = ARCHIVE_OK; + char *tail; + char *head; + int last; char c; int r; struct stat st; + int restore_pwd; + + /* Nothing to do here if name is empty */ + if(path[0] == '\0') + return (ARCHIVE_OK); /* * Guard against symlink tricks. Reject any archive entry whose * destination would be altered by a symlink. - */ - /* Whatever we checked last time doesn't need to be re-checked. */ - pn = a->name; - if (archive_strlen(&(a->path_safe)) > 0) { - char *p = a->path_safe.s; - while ((*pn != '\0') && (*p == *pn)) - ++p, ++pn; - } - c = pn[0]; - /* Keep going until we've checked the entire name. */ - while (pn[0] != '\0' && (pn[0] != '/' || pn[1] != '\0')) { + * + * Walk the filename in chunks separated by '/'. For each segment: + * - if it doesn't exist, continue + * - if it's symlink, abort or remove it + * - if it's a directory and it's not the last chunk, cd into it + * As we go: + * head points to the current (relative) path + * tail points to the temporary \0 terminating the segment we're currently examining + * c holds what used to be in *tail + * last is 1 if this is the last tail + */ + restore_pwd = open(".", O_RDONLY | O_BINARY | O_CLOEXEC); + __archive_ensure_cloexec_flag(restore_pwd); + if (restore_pwd < 0) + return (ARCHIVE_FATAL); + head = path; + tail = path; + last = 0; + + /* TODO: reintroduce a safe cache here? */ + + /* Keep going until we've checked the entire name. + * head, tail, path all alias the same string, which is + * temporarily zeroed at tail, so be careful restoring the + * stashed (c=tail[0]) for error messages. + * Exiting the loop with break is okay; continue is not. + */ + while (!last) { + /* Skip the separator we just consumed, plus any adjacent ones */ + while (*tail == '/') + ++tail; /* Skip the next path element. */ - while (*pn != '\0' && *pn != '/') - ++pn; - c = pn[0]; - pn[0] = '\0'; + while (*tail != '\0' && *tail != '/') + ++tail; + /* is this the last path component? */ + last = (tail[0] == '\0') || (tail[0] == '/' && tail[1] == '\0'); + /* temporarily truncate the string here */ + c = tail[0]; + tail[0] = '\0'; /* Check that we haven't hit a symlink. */ - r = lstat(a->name, &st); + r = lstat(head, &st); if (r != 0) { + tail[0] = c; /* We've hit a dir that doesn't exist; stop now. */ if (errno == ENOENT) break; + /* Treat any other error as fatal - best to be paranoid here */ + if(error_number) *error_number = errno; + if(error_string) + archive_string_sprintf(error_string, + "Could not stat %s", + path); + res = (ARCHIVE_FATAL); + break; + } else if (S_ISDIR(st.st_mode)) { + if (!last) { + if (chdir(head) != 0) { + tail[0] = c; + if(error_number) *error_number = errno; + if(error_string) + archive_string_sprintf(error_string, + "Could not chdir %s", + path); + res = (ARCHIVE_FATAL); + break; + } + /* Our view is now from inside this dir: */ + head = tail + 1; + } } else if (S_ISLNK(st.st_mode)) { - if (c == '\0') { + if (last) { /* * Last element is symlink; remove it * so we can overwrite it with the * item being extracted. */ - if (unlink(a->name)) { - archive_set_error(&a->archive, errno, - "Could not remove symlink %s", - a->name); - pn[0] = c; - return (ARCHIVE_FAILED); + if (unlink(head)) { + tail[0] = c; + if(error_number) *error_number = errno; + if(error_string) + archive_string_sprintf(error_string, + "Could not remove symlink %s", + path); + res = (ARCHIVE_FAILED); + break; } - a->pst = NULL; /* * Even if we did remove it, a warning * is in order. The warning is silly, * though, if we're just replacing one * symlink with another symlink. */ + tail[0] = c; + /* FIXME: not sure how important this is to restore if (!S_ISLNK(a->mode)) { - archive_set_error(&a->archive, 0, - "Removing symlink %s", - a->name); + if(error_number) *error_number = 0; + if(error_string) + archive_string_sprintf(error_string, + "Removing symlink %s", + path); } + */ /* Symlink gone. No more problem! */ - pn[0] = c; - return (0); - } else if (a->flags & ARCHIVE_EXTRACT_UNLINK) { + res = (ARCHIVE_OK); + break; + } else if (flags & ARCHIVE_EXTRACT_UNLINK) { /* User asked us to remove problems. */ - if (unlink(a->name) != 0) { - archive_set_error(&a->archive, 0, - "Cannot remove intervening symlink %s", - a->name); - pn[0] = c; - return (ARCHIVE_FAILED); + if (unlink(head) != 0) { + tail[0] = c; + if(error_number) *error_number = 0; + if(error_string) + archive_string_sprintf(error_string, + "Cannot remove intervening symlink %s", + path); + res = (ARCHIVE_FAILED); + break; } - a->pst = NULL; } else { - archive_set_error(&a->archive, 0, - "Cannot extract through symlink %s", - a->name); - pn[0] = c; - return (ARCHIVE_FAILED); + tail[0] = c; + if(error_number) *error_number = 0; + if(error_string) + archive_string_sprintf(error_string, + "Cannot extract through symlink %s", + path); + res = (ARCHIVE_FAILED); + break; } } + /* be sure to always maintain this */ + tail[0] = c; } - pn[0] = c; - /* We've checked and/or cleaned the whole path, so remember it. */ - archive_strcpy(&a->path_safe, a->name); - return (ARCHIVE_OK); + /* Catches loop exits via break */ + tail[0] = c; +#ifdef HAVE_FCHDIR + /* If we changed directory above, restore it here. */ + if (restore_pwd >= 0) { + r = fchdir(restore_pwd); + if (r != 0) { + if(error_number) *error_number = 0; + if(error_string) + archive_string_sprintf(error_string, + "Cannot extract through symlink %s", + path); + } + close(restore_pwd); + restore_pwd = -1; + if (r != 0) { + res = (ARCHIVE_FATAL); + } + } +#endif + /* TODO: reintroduce a safe cache here? */ + return res; #endif } +/* + * Check a->name for symlinks, returning ARCHIVE_OK if its clean, otherwise + * calls archive_set_error and returns ARCHIVE_{FATAL,FAILED} + */ +static int +check_symlinks(struct archive_write_disk *a) +{ + struct archive_string error_string; + int error_number; + int rc; + archive_string_init(&error_string); + rc = check_symlinks_fsobj(a->name, &error_number, &error_string, a->flags); + if (rc != ARCHIVE_OK) { + archive_set_error(&a->archive, error_number, "%s", error_string.s); + } + archive_string_free(&error_string); + a->pst = NULL; /* to be safe */ + return rc; +} + + #if defined(__CYGWIN__) /* * 1. Convert a path separator from '\' to '/' . @@ -2509,15 +2652,17 @@ cleanup_pathname_win(struct archive_writ * is set) if the path is absolute. */ static int -cleanup_pathname(struct archive_write_disk *a) +cleanup_pathname_fsobj(char *path, int *error_number, struct archive_string *error_string, int flags) { char *dest, *src; char separator = '\0'; - dest = src = a->name; + dest = src = path; if (*src == '\0') { - archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, - "Invalid empty pathname"); + if (error_number) *error_number = ARCHIVE_ERRNO_MISC; + if (error_string) + archive_string_sprintf(error_string, + "Invalid empty pathname"); return (ARCHIVE_FAILED); } @@ -2555,10 +2700,11 @@ cleanup_pathname(struct archive_write_di } else if (src[1] == '.') { if (src[2] == '/' || src[2] == '\0') { /* Conditionally warn about '..' */ - if (a->flags & ARCHIVE_EXTRACT_SECURE_NODOTDOT) { - archive_set_error(&a->archive, - ARCHIVE_ERRNO_MISC, - "Path contains '..'"); + if (flags & ARCHIVE_EXTRACT_SECURE_NODOTDOT) { + if (error_number) *error_number = ARCHIVE_ERRNO_MISC; + if (error_string) + archive_string_sprintf(error_string, + "Path contains '..'"); return (ARCHIVE_FAILED); } } @@ -2589,7 +2735,7 @@ cleanup_pathname(struct archive_write_di * We've just copied zero or more path elements, not including the * final '/'. */ - if (dest == a->name) { + if (dest == path) { /* * Nothing got copied. The path must have been something * like '.' or '/' or './' or '/././././/./'. @@ -2604,6 +2750,21 @@ cleanup_pathname(struct archive_write_di return (ARCHIVE_OK); } +static int +cleanup_pathname(struct archive_write_disk *a) +{ + struct archive_string error_string; + int error_number; + int rc; + archive_string_init(&error_string); + rc = cleanup_pathname_fsobj(a->name, &error_number, &error_string, a->flags); + if (rc != ARCHIVE_OK) { + archive_set_error(&a->archive, error_number, "%s", error_string.s); + } + archive_string_free(&error_string); + return rc; +} + /* * Create the parent directory of the specified path, assuming path * is already in mutable storage.
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