9468ea06d
Denys Vlasenko
2021-06-24
Subject
lsattr,chattr: do not open e.g. device files unless asked directly; do not follow links
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Commit Diff GitHub →
e2fsprogs/chattr.c+6 -3
| @@ -162,8 +162,6 @@ static void change_attributes(const char *name, struct globals *gp) | |
| bb_perror_msg("can't stat '%s'", name); | |
| return; | |
| } | |
| - | if (S_ISLNK(st.st_mode) && gp->recursive) |
| - | return; |
| /* Don't try to open device files, fifos etc. We probably | |
| * ought to display an error if the file was explicitly given | |
| @@ -172,7 +170,12 @@ static void change_attributes(const char *name, struct globals *gp) | |
| if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode)) | |
| return; | |
| - | fd = open_or_warn(name, O_RDONLY | O_NONBLOCK); /* neither read nor write asked for */ |
| + | /* There is no way to run needed ioctls on a symlink. |
| + | * open(O_PATH | O_NOFOLLOW) _can_ be used to get a fd referring to the symlink, |
| + | * but ioctls fail on such a fd (tried on 4.12.0 kernel). |
| + | * e2fsprogs-1.46.2 uses open(O_NOFOLLOW), it fails on symlinks. |
| + | */ |
| + | fd = open_or_warn(name, O_RDONLY | O_NONBLOCK | O_NOCTTY | O_NOFOLLOW); |
| if (fd >= 0) { | |
| int r; | |
e2fsprogs/lsattr.c+12 -3
| @@ -49,8 +49,13 @@ static void list_attributes(const char *name) | |
| unsigned fsflags; | |
| int fd, r; | |
| - | fd = open_or_warn(name, O_RDONLY | O_NONBLOCK); /* neither read nor write asked for */ |
| - | if (fd < 0) /* for example, dangling links */ |
| + | /* There is no way to run needed ioctls on a symlink. |
| + | * open(O_PATH | O_NOFOLLOW) _can_ be used to get a fd referring to the symlink, |
| + | * but ioctls fail on such a fd (tried on 4.12.0 kernel). |
| + | * e2fsprogs-1.46.2 uses open(O_NOFOLLOW), it fails on symlinks. |
| + | */ |
| + | fd = open_or_warn(name, O_RDONLY | O_NONBLOCK | O_NOCTTY | O_NOFOLLOW); |
| + | if (fd < 0) |
| return; | |
| if (option_mask32 & OPT_PROJID) { | |
| @@ -102,8 +107,12 @@ static int FAST_FUNC lsattr_dir_proc(const char *dir_name, | |
| if (lstat(path, &st) != 0) | |
| bb_perror_msg("can't stat '%s'", path); | |
| + | |
| else if (de->d_name[0] != '.' || (option_mask32 & OPT_ALL)) { | |
| - | list_attributes(path); |
| + | /* Don't try to open device files, fifos etc */ |
| + | if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode) || S_ISDIR(st.st_mode)) |
| + | list_attributes(path); |
| + | |
| if (S_ISDIR(st.st_mode) && (option_mask32 & OPT_RECUR) | |
| && !DOT_OR_DOTDOT(de->d_name) | |
| ) { | |