8c4bccb83
Denys Vlasenko
2024-10-07
Subject
hush: fix "type ./cat" and "command -v ./cat" to not scan PATH
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shell/hush.c+33 -13
| @@ -8201,27 +8201,29 @@ static int setup_redirects(struct command *prog, struct squirrel **sqp) | |
| return 0; | |
| } | |
| - | /* Find a file in PATH, not necessarily executable */ |
| + | /* Find a file in PATH, not necessarily executable |
| + | * Name is known to not contain '/'. |
| + | */ |
| //TODO: shares code with find_executable() in libbb, factor out? | |
| - | static char *find_in_path(const char *arg) |
| + | static char *find_in_PATH(const char *name) |
| { | |
| - | char *ret = NULL; |
| + | char *ret; |
| const char *PATH = get_local_var_value("PATH"); | |
| if (!PATH) | |
| return NULL; | |
| - | |
| + | ret = NULL; |
| while (1) { | |
| const char *end = strchrnul(PATH, ':'); | |
| int sz = end - PATH; /* must be int! */ | |
| free(ret); | |
| if (sz != 0) { | |
| - | ret = xasprintf("%.*s/%s", sz, PATH, arg); |
| + | ret = xasprintf("%.*s/%s", sz, PATH, name); |
| } else { | |
| /* We have xxx::yyyy in $PATH, | |
| * it means "use current dir" */ | |
| - | ret = xstrdup(arg); |
| + | ret = xstrdup(name); |
| } | |
| if (access(ret, F_OK) == 0) | |
| break; | |
| @@ -8236,6 +8238,24 @@ static char *find_in_path(const char *arg) | |
| return ret; | |
| } | |
| + | #if ENABLE_HUSH_TYPE || ENABLE_HUSH_COMMAND |
| + | static char *find_executable_in_PATH(const char *name) |
| + | { |
| + | char *PATH; |
| + | if (strchr(name, '/')) { |
| + | /* Name with '/' is tested verbatim, with no PATH traversal: |
| + | * "cd /bin; type ./cat" should print "./cat is ./cat", |
| + | * NOT "./cat is /bin/./cat" |
| + | */ |
| + | if (file_is_executable(name)) |
| + | return xstrdup(name); |
| + | return NULL; |
| + | } |
| + | PATH = (char*)get_local_var_value("PATH"); |
| + | return find_executable(name, &PATH); /* path == NULL is ok */ |
| + | } |
| + | #endif |
| + | |
| static const struct built_in_command *find_builtin_helper(const char *name, | |
| const struct built_in_command *x, | |
| const struct built_in_command *end) | |
| @@ -8645,10 +8665,11 @@ static void if_command_vV_print_and_exit(char opt_vV, char *cmd, const char *exp | |
| to_free = NULL; | |
| if (!explanation) { | |
| - | char *path = (char*)get_local_var_value("PATH"); |
| - | explanation = to_free = find_executable(cmd, &path); /* path == NULL is ok */ |
| - | if (!explanation) |
| + | explanation = to_free = find_executable_in_PATH(cmd); |
| + | if (!explanation) { |
| + | bb_error_msg("%s: %s: not found", "command", cmd); |
| _exit(1); /* PROG was not found */ | |
| + | } |
| if (opt_vV != 'V') | |
| cmd = to_free; /* -v PROG prints "/path/to/PROG" */ | |
| } | |
| @@ -11075,12 +11096,11 @@ static int FAST_FUNC builtin_type(char **argv) | |
| else if (find_builtin(*argv)) | |
| type = "a shell builtin"; | |
| else { | |
| - | char *pathvar = (char*)get_local_var_value("PATH"); |
| - | path = find_executable(*argv, &pathvar); |
| + | path = find_executable_in_PATH(*argv); |
| if (path) | |
| type = path; | |
| else { | |
| - | bb_error_msg("type: %s: not found", *argv); |
| + | bb_error_msg("%s: %s: not found", "type", *argv); |
| ret = EXIT_FAILURE; | |
| continue; | |
| } | |
| @@ -11710,7 +11730,7 @@ static int FAST_FUNC builtin_source(char **argv) | |
| } | |
| arg_path = NULL; | |
| if (!strchr(filename, '/')) { | |
| - | arg_path = find_in_path(filename); |
| + | arg_path = find_in_PATH(filename); |
| if (arg_path) | |
| filename = arg_path; | |
| else if (!ENABLE_HUSH_BASH_SOURCE_CURDIR) { | |