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Merge pull request #19709 from keszybz/sysusers-no-proc

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Add more logs and make sysusers works in dnf --installroot
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2021-05-25 08:20:56 +02:00 committed by GitHub
commit dd30da133a
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 116 additions and 71 deletions
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4
src/basic/copy.c
View File

@ -1243,7 +1243,7 @@ int copy_access(int fdf, int fdt) {
return 0;
}
int copy_rights(int fdf, int fdt) {
int copy_rights_with_fallback(int fdf, int fdt, const char *patht) {
struct stat st;
assert(fdf >= 0);
@ -1254,7 +1254,7 @@ int copy_rights(int fdf, int fdt) {
if (fstat(fdf, &st) < 0)
return -errno;
return fchmod_and_chown(fdt, st.st_mode & 07777, st.st_uid, st.st_gid);
return fchmod_and_chown_with_fallback(fdt, patht, st.st_mode & 07777, st.st_uid, st.st_gid);
}
int copy_xattr(int fdf, int fdt) {

5
src/basic/copy.h
View File

@ -64,5 +64,8 @@ static inline int copy_bytes(int fdf, int fdt, uint64_t max_bytes, CopyFlags cop
int copy_times(int fdf, int fdt, CopyFlags flags);
int copy_access(int fdf, int fdt);
int copy_rights(int fdf, int fdt);
int copy_rights_with_fallback(int fdf, int fdt, const char *patht);
static inline int copy_rights(int fdf, int fdt) {
return copy_rights_with_fallback(fdf, fdt, NULL); /* no fallback */
}
int copy_xattr(int fdf, int fdt);

28
src/basic/fs-util.c
View File

@ -227,7 +227,7 @@ int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
return fchmod_and_chown(fd, mode, uid, gid);
}
int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
int fchmod_and_chown_with_fallback(int fd, const char *path, mode_t mode, uid_t uid, gid_t gid) {
bool do_chown, do_chmod;
struct stat st;
int r;
@ -238,7 +238,11 @@ int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
* unaffected if the uid/gid is changed, i.e. it undoes implicit suid/sgid dropping the kernel does
* on chown().
*
* This call is happy with O_PATH fds. */
* This call is happy with O_PATH fds.
*
* If path is given, allow a fallback path which does not use /proc/self/fd/. On any normal system
* /proc will be mounted, but in certain improperly assembled environments it might not be. This is
* less secure (potential TOCTOU), so should only be used after consideration. */
if (fstat(fd, &st) < 0)
return -errno;
@ -263,8 +267,14 @@ int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
if (((minimal ^ st.st_mode) & 07777) != 0) {
r = fchmod_opath(fd, minimal & 07777);
if (r < 0)
return r;
if (r < 0) {
if (!path || r != -ENOSYS)
return r;
/* Fallback path which doesn't use /proc/self/fd/. */
if (chmod(path, minimal & 07777) < 0)
return -errno;
}
}
}
@ -274,8 +284,14 @@ int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
if (do_chmod) {
r = fchmod_opath(fd, mode & 07777);
if (r < 0)
return r;
if (r < 0) {
if (!path || r != -ENOSYS)
return r;
/* Fallback path which doesn't use /proc/self/fd/. */
if (chmod(path, mode & 07777) < 0)
return -errno;
}
}
return do_chown || do_chmod;

5
src/basic/fs-util.h
View File

@ -34,7 +34,10 @@ int readlink_value(const char *p, char **ret);
int readlink_and_make_absolute(const char *p, char **r);
int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid);
int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid);
int fchmod_and_chown_with_fallback(int fd, const char *path, mode_t mode, uid_t uid, gid_t gid);
static inline int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
return fchmod_and_chown_with_fallback(fd, NULL, mode, uid, gid); /* no fallback */
}
int fchmod_umask(int fd, mode_t mode);
int fchmod_opath(int fd, mode_t m);

145
src/sysusers/sysusers.c
View File

@ -391,17 +391,21 @@ static int write_temporary_passwd(const char *passwd_path, FILE **tmpfile, char
r = fopen_temporary_label("/etc/passwd", passwd_path, &passwd, &passwd_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to open temporary copy of %s: %m", passwd_path);
original = fopen(passwd_path, "re");
if (original) {
r = copy_rights(fileno(original), fileno(passwd));
/* Allow fallback path for when /proc is not mounted. On any normal system /proc will be
* mounted, but e.g. when 'dnf --installroot' is used, it might not be. There is no security
* relevance here, since the environment is ultimately trusted, and not requiring /proc makes
* it easier to depend on sysusers in packaging scripts and suchlike. */
r = copy_rights_with_fallback(fileno(original), fileno(passwd), passwd_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to copy permissions from %s to %s: %m",
passwd_path, passwd_tmp);
while ((r = fgetpwent_sane(original, &pw)) > 0) {
i = ordered_hashmap_get(users, pw->pw_name);
if (i && i->todo_user)
return log_error_errno(SYNTHETIC_ERRNO(EEXIST),
@ -419,16 +423,17 @@ static int write_temporary_passwd(const char *passwd_path, FILE **tmpfile, char
r = putpwent_sane(pw, passwd);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing user \"%s\" to temporary passwd file: %m",
pw->pw_name);
}
if (r < 0)
return r;
return log_debug_errno(r, "Failed to read %s: %m", passwd_path);
} else {
if (errno != ENOENT)
return -errno;
return log_debug_errno(errno, "Failed to open %s: %m", passwd_path);
if (fchmod(fileno(passwd), 0644) < 0)
return -errno;
return log_debug_errno(errno, "Failed to fchmod %s: %m", passwd_tmp);
}
ORDERED_HASHMAP_FOREACH(i, todo_uids) {
@ -464,25 +469,27 @@ static int write_temporary_passwd(const char *passwd_path, FILE **tmpfile, char
r = putpwent_sane(&n, passwd);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add new user \"%s\" to temporary passwd file: %m",
pw->pw_name);
}
/* Append the remaining NIS entries if any */
while (pw) {
r = putpwent_sane(pw, passwd);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing user \"%s\" to temporary passwd file: %m",
pw->pw_name);
r = fgetpwent_sane(original, &pw);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to read %s: %m", passwd_path);
if (r == 0)
break;
}
r = fflush_and_check(passwd);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to flush %s: %m", passwd_tmp);
*tmpfile = TAKE_PTR(passwd);
*tmpfile_path = TAKE_PTR(passwd_tmp);
@ -503,19 +510,19 @@ static int write_temporary_shadow(const char *shadow_path, FILE **tmpfile, char
r = fopen_temporary_label("/etc/shadow", shadow_path, &shadow, &shadow_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to open temporary copy of %s: %m", shadow_path);
lstchg = (long) (now(CLOCK_REALTIME) / USEC_PER_DAY);
original = fopen(shadow_path, "re");
if (original) {
r = copy_rights(fileno(original), fileno(shadow));
r = copy_rights_with_fallback(fileno(original), fileno(shadow), shadow_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to copy permissions from %s to %s: %m",
shadow_path, shadow_tmp);
while ((r = fgetspent_sane(original, &sp)) > 0) {
i = ordered_hashmap_get(users, sp->sp_namp);
if (i && i->todo_user) {
/* we will update the existing entry */
@ -533,16 +540,18 @@ static int write_temporary_shadow(const char *shadow_path, FILE **tmpfile, char
r = putspent_sane(sp, shadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing user \"%s\" to temporary shadow file: %m",
sp->sp_namp);
}
if (r < 0)
return r;
return log_debug_errno(r, "Failed to read %s: %m", shadow_path);
} else {
if (errno != ENOENT)
return -errno;
return log_debug_errno(errno, "Failed to open %s: %m", shadow_path);
if (fchmod(fileno(shadow), 0000) < 0)
return -errno;
return log_debug_errno(errno, "Failed to fchmod %s: %m", shadow_tmp);
}
ORDERED_HASHMAP_FOREACH(i, todo_uids) {
@ -591,18 +600,20 @@ static int write_temporary_shadow(const char *shadow_path, FILE **tmpfile, char
r = putspent_sane(&n, shadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add new user \"%s\" to temporary shadow file: %m",
sp->sp_namp);
}
/* Append the remaining NIS entries if any */
while (sp) {
r = putspent_sane(sp, shadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing user \"%s\" to temporary shadow file: %m",
sp->sp_namp);
r = fgetspent_sane(original, &sp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to read %s: %m", shadow_path);
if (r == 0)
break;
}
@ -611,7 +622,7 @@ static int write_temporary_shadow(const char *shadow_path, FILE **tmpfile, char
r = fflush_sync_and_check(shadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to flush %s: %m", shadow_tmp);
*tmpfile = TAKE_PTR(shadow);
*tmpfile_path = TAKE_PTR(shadow_tmp);
@ -632,14 +643,15 @@ static int write_temporary_group(const char *group_path, FILE **tmpfile, char **
r = fopen_temporary_label("/etc/group", group_path, &group, &group_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to open temporary copy of %s: %m", group_path);
original = fopen(group_path, "re");
if (original) {
r = copy_rights(fileno(original), fileno(group));
r = copy_rights_with_fallback(fileno(original), fileno(group), group_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to copy permissions from %s to %s: %m",
group_path, group_tmp);
while ((r = fgetgrent_sane(original, &gr)) > 0) {
/* Safety checks against name and GID collisions. Normally,
@ -664,18 +676,19 @@ static int write_temporary_group(const char *group_path, FILE **tmpfile, char **
r = putgrent_with_members(gr, group);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing group \"%s\" to temporary group file: %m",
gr->gr_name);
if (r > 0)
group_changed = true;
}
if (r < 0)
return r;
return log_debug_errno(r, "Failed to read %s: %m", group_path);
} else {
if (errno != ENOENT)
return -errno;
return log_debug_errno(errno, "Failed to open %s: %m", group_path);
if (fchmod(fileno(group), 0644) < 0)
return -errno;
return log_debug_errno(errno, "Failed to fchmod %s: %m", group_tmp);
}
ORDERED_HASHMAP_FOREACH(i, todo_gids) {
@ -687,7 +700,8 @@ static int write_temporary_group(const char *group_path, FILE **tmpfile, char **
r = putgrent_with_members(&n, group);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add new group \"%s\" to temporary group file: %m",
gr->gr_name);
group_changed = true;
}
@ -696,18 +710,19 @@ static int write_temporary_group(const char *group_path, FILE **tmpfile, char **
while (gr) {
r = putgrent_sane(gr, group);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing group \"%s\" to temporary group file: %m",
gr->gr_name);
r = fgetgrent_sane(original, &gr);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to read %s: %m", group_path);
if (r == 0)
break;
}
r = fflush_sync_and_check(group);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to flush %s: %m", group_tmp);
if (group_changed) {
*tmpfile = TAKE_PTR(group);
@ -729,15 +744,16 @@ static int write_temporary_gshadow(const char * gshadow_path, FILE **tmpfile, ch
r = fopen_temporary_label("/etc/gshadow", gshadow_path, &gshadow, &gshadow_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to open temporary copy of %s: %m", gshadow_path);
original = fopen(gshadow_path, "re");
if (original) {
struct sgrp *sg;
r = copy_rights(fileno(original), fileno(gshadow));
r = copy_rights_with_fallback(fileno(original), fileno(gshadow), gshadow_tmp);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to copy permissions from %s to %s: %m",
gshadow_path, gshadow_tmp);
while ((r = fgetsgent_sane(original, &sg)) > 0) {
@ -749,7 +765,8 @@ static int write_temporary_gshadow(const char * gshadow_path, FILE **tmpfile, ch
r = putsgent_with_members(sg, gshadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add existing group \"%s\" to temporary gshadow file: %m",
sg->sg_namp);
if (r > 0)
group_changed = true;
}
@ -758,9 +775,9 @@ static int write_temporary_gshadow(const char * gshadow_path, FILE **tmpfile, ch
} else {
if (errno != ENOENT)
return -errno;
return log_debug_errno(errno, "Failed to open %s: %m", gshadow_path);
if (fchmod(fileno(gshadow), 0000) < 0)
return -errno;
return log_debug_errno(errno, "Failed to fchmod %s: %m", gshadow_tmp);
}
ORDERED_HASHMAP_FOREACH(i, todo_gids) {
@ -771,29 +788,28 @@ static int write_temporary_gshadow(const char * gshadow_path, FILE **tmpfile, ch
r = putsgent_with_members(&n, gshadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add new group \"%s\" to temporary gshadow file: %m",
n.sg_namp);
group_changed = true;
}
r = fflush_sync_and_check(gshadow);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to flush %s: %m", gshadow_tmp);
if (group_changed) {
*tmpfile = TAKE_PTR(gshadow);
*tmpfile_path = TAKE_PTR(gshadow_tmp);
}
return 0;
#else
return 0;
#endif
return 0;
}
static int write_files(void) {
_cleanup_fclose_ FILE *passwd = NULL, *group = NULL, *shadow = NULL, *gshadow = NULL;
_cleanup_(unlink_and_freep) char *passwd_tmp = NULL, *group_tmp = NULL, *shadow_tmp = NULL, *gshadow_tmp = NULL;
const char *passwd_path = NULL, *group_path = NULL, *shadow_path = NULL, *gshadow_path = NULL;
const char *passwd_path, *shadow_path, *group_path, *gshadow_path;
int r;
passwd_path = prefix_roota(arg_root, "/etc/passwd");
@ -821,31 +837,31 @@ static int write_files(void) {
if (group) {
r = make_backup("/etc/group", group_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to make backup %s: %m", group_path);
}
if (gshadow) {
r = make_backup("/etc/gshadow", gshadow_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to make backup %s: %m", gshadow_path);
}
if (passwd) {
r = make_backup("/etc/passwd", passwd_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to make backup %s: %m", passwd_path);
}
if (shadow) {
r = make_backup("/etc/shadow", shadow_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to make backup %s: %m", shadow_path);
}
/* And make the new files count */
if (group) {
r = rename_and_apply_smack_floor_label(group_tmp, group_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to rename %s to %s: %m",
group_tmp, group_path);
group_tmp = mfree(group_tmp);
if (!arg_root && !arg_image)
@ -854,7 +870,8 @@ static int write_files(void) {
if (gshadow) {
r = rename_and_apply_smack_floor_label(gshadow_tmp, gshadow_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to rename %s to %s: %m",
gshadow_tmp, gshadow_path);
gshadow_tmp = mfree(gshadow_tmp);
}
@ -862,7 +879,8 @@ static int write_files(void) {
if (passwd) {
r = rename_and_apply_smack_floor_label(passwd_tmp, passwd_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to rename %s to %s: %m",
passwd_tmp, passwd_path);
passwd_tmp = mfree(passwd_tmp);
@ -872,7 +890,8 @@ static int write_files(void) {
if (shadow) {
r = rename_and_apply_smack_floor_label(shadow_tmp, shadow_path);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to rename %s to %s: %m",
shadow_tmp, shadow_path);
shadow_tmp = mfree(shadow_tmp);
}
@ -881,10 +900,6 @@ static int write_files(void) {
}
static int uid_is_ok(uid_t uid, const char *name, bool check_with_gid) {
struct passwd *p;
struct group *g;
const char *n;
Item *i;
/* Let's see if we already have assigned the UID a second time */
if (ordered_hashmap_get(todo_uids, UID_TO_PTR(uid)))
@ -893,6 +908,8 @@ static int uid_is_ok(uid_t uid, const char *name, bool check_with_gid) {
/* Try to avoid using uids that are already used by a group
* that doesn't have the same name as our new user. */
if (check_with_gid) {
Item *i;
i = ordered_hashmap_get(todo_gids, GID_TO_PTR(uid));
if (i && !streq(i->name, name))
return 0;
@ -903,6 +920,8 @@ static int uid_is_ok(uid_t uid, const char *name, bool check_with_gid) {
return 0;
if (check_with_gid) {
const char *n;
n = hashmap_get(database_by_gid, GID_TO_PTR(uid));
if (n && !streq(n, name))
return 0;
@ -910,6 +929,9 @@ static int uid_is_ok(uid_t uid, const char *name, bool check_with_gid) {
/* Let's also check via NSS, to avoid UID clashes over LDAP and such, just in case */
if (!arg_root) {
struct passwd *p;
struct group *g;
errno = 0;
p = getpwuid(uid);
if (p)
@ -1109,7 +1131,8 @@ static int add_user(Item *i) {
i->name, i->uid, i->gid);
i->todo_user = true;
log_info("Creating user %s (%s) with uid " UID_FMT " and gid " GID_FMT ".", i->name, strna(i->description), i->uid, i->gid);
log_info("Creating user %s (%s) with uid " UID_FMT " and gid " GID_FMT ".",
i->name, strna(i->description), i->uid, i->gid);
return 0;
}