refactor meta character filtering

6 files changed, 73 insertions, 56 deletions

diff --git a/src/fcopy/main.c b/src/fcopy/main.c
index c64d20127..e56d853c8 100644
--- a/src/fcopy/main.c
+++ b/src/fcopy/main.c
@@ -472,18 +472,12 @@ int main(int argc, char **argv) {
         size_t len = strlen(src);
         while (len > 1 && src[len - 1] == '/')
                 src[--len] = '\0';
-        if (strcspn(src, "\\*&!?\"'<>%^(){}[];,") != len) {
-                fprintf(stderr, "Error fcopy: invalid source file name %s\n", src);
-                exit(1);
-        }
+        reject_meta_chars(src, 0);
 
         len = strlen(dest);
         while (len > 1 && dest[len - 1] == '/')
                 dest[--len] = '\0';
-        if (strcspn(dest, "\\*&!?\"'<>%^(){}[];,~") != len) {
-                fprintf(stderr, "Error fcopy: invalid dest file name %s\n", dest);
-                exit(1);
-        }
+        reject_meta_chars(dest, 0);
 
         // the destination should be a directory;
         struct stat s;
diff --git a/src/firejail/fs_lib.c b/src/firejail/fs_lib.c
index 194a980f4..848691a56 100644
--- a/src/firejail/fs_lib.c
+++ b/src/firejail/fs_lib.c
@@ -276,9 +276,9 @@ static void install_list_entry(const char *lib) {
         assert(lib);
 
         // filename check
-        int len = strlen(lib);
-        if (strcspn(lib, "\\&!?\"'<>%^(){}[];,") != (size_t)len ||
-        strstr(lib, "..")) {
+        reject_meta_chars(lib, 1);
+
+        if (strstr(lib, "..")) {
                 fprintf(stderr, "Error: \"%s\" is an invalid library\n", lib);
                 exit(1);
         }
diff --git a/src/firejail/macros.c b/src/firejail/macros.c
index 74d529504..3f9460041 100644
--- a/src/firejail/macros.c
+++ b/src/firejail/macros.c
@@ -265,28 +265,6 @@ char *expand_macros(const char *path) {
         return rv;
 }
 
-// replace control characters with a '?'
-static char *fix_control_chars(const char *fname) {
-        assert(fname);
-
-        size_t len = strlen(fname);
-        char *rv = malloc(len + 1);
-        if (!rv)
-                errExit("malloc");
-
-        size_t i = 0;
-        while (fname[i] != '\0') {
-                if (iscntrl((unsigned char) fname[i]))
-                        rv[i] = '?';
-                else
-                        rv[i] = fname[i];
-                i++;
-        }
-        rv[i] = '\0';
-
-        return rv;
-}
-
 void invalid_filename(const char *fname, int globbing) {
 //      EUID_ASSERT();
         assert(fname);
@@ -304,24 +282,5 @@ void invalid_filename(const char *fname, int globbing) {
                         return;
         }
 
-        size_t i = 0;
-        while (ptr[i] != '\0') {
-                if (iscntrl((unsigned char) ptr[i])) {
-                        char *new = fix_control_chars(fname);
-                        fprintf(stderr, "Error: \"%s\" is an invalid filename: no control characters allowed\n", new);
-                        exit(1);
-                }
-                i++;
-        }
-
-        char *reject;
-        if (globbing)
-                reject = "\\&!\"<>%^{};,"; // file globbing ('*?[]') is allowed
-        else
-                reject = "\\&!?\"<>%^{};,*[]";
-        char *c = strpbrk(ptr, reject);
-        if (c) {
-                fprintf(stderr, "Error: \"%s\" is an invalid filename: rejected character: \"%c\"\n", fname, *c);
-                exit(1);
-        }
+        reject_meta_chars(ptr, globbing);
 }
diff --git a/src/fnetfilter/main.c b/src/fnetfilter/main.c
index 081408ab3..a89e12933 100644
--- a/src/fnetfilter/main.c
+++ b/src/fnetfilter/main.c
@@ -187,10 +187,9 @@ printf("\n");
         char *command = (argc == 3)? argv[1]: NULL;
 //printf("command %s\n", command);
 //printf("destfile %s\n", destfile);
+
         // destfile is a real filename
-        int len = strlen(destfile);
-        if (strcspn(destfile, "\\&!?\"'<>%^(){};,*[]") != (size_t)len)
-                err_exit_cannot_open_file(destfile);
+        reject_meta_chars(destfile, 0);
 
         // handle default config (command = NULL, destfile)
         if (command == NULL) {
diff --git a/src/include/common.h b/src/include/common.h
index f72ec9738..c9640435a 100644
--- a/src/include/common.h
+++ b/src/include/common.h
@@ -140,6 +140,11 @@ char *pid_proc_comm(const pid_t pid);
 char *pid_proc_cmdline(const pid_t pid);
 int pid_proc_cmdline_x11_xpra_xephyr(const pid_t pid);
 int pid_hidepid(void);
+char *do_replace_cntrl_chars(char *str, char c);
+char *replace_cntrl_chars(const char *str, char c);
+int has_cntrl_chars(const char *str);
+void reject_cntrl_chars(const char *fname);
+void reject_meta_chars(const char *fname, int globbing);
 void warn_dumpable(void);
 const char *gnu_basename(const char *path);
 int *str_to_int_array(const char *str, size_t *sz);
diff --git a/src/lib/common.c b/src/lib/common.c
index 91d5125b1..8e84fab26 100644
--- a/src/lib/common.c
+++ b/src/lib/common.c
@@ -321,6 +321,66 @@ const char *gnu_basename(const char *path) {
         return last_slash+1;
 }
 
+char *do_replace_cntrl_chars(char *str, char c) {
+        if (str) {
+                size_t i;
+                for (i = 0; str[i]; i++) {
+                        if (iscntrl((unsigned char) str[i]))
+                                str[i] = c;
+                }
+        }
+        return str;
+}
+
+char *replace_cntrl_chars(const char *str, char c) {
+        assert(str);
+
+        char *rv = strdup(str);
+        if (!rv)
+                errExit("strdup");
+
+        do_replace_cntrl_chars(rv, c);
+        return rv;
+}
+
+int has_cntrl_chars(const char *str) {
+        assert(str);
+
+        size_t i;
+        for (i = 0; str[i]; i++) {
+                if (iscntrl((unsigned char) str[i]))
+                        return 1;
+        }
+        return 0;
+}
+
+void reject_cntrl_chars(const char *fname) {
+        assert(fname);
+
+        if (has_cntrl_chars(fname)) {
+                char *fname_print = replace_cntrl_chars(fname, '?');
+
+                fprintf(stderr, "Error: \"%s\" is an invalid filename: no control characters are allowed\n", fname_print);
+                exit(1);
+        }
+}
+
+void reject_meta_chars(const char *fname, int globbing) {
+        assert(fname);
+
+        reject_cntrl_chars(fname);
+
+        const char *reject = "\\&!?\"<>%^{};,*[]";
+        if (globbing)
+                reject = "\\&!\"<>%^{};,"; // file globbing ('*?[]') is allowed
+
+        const char *c = strpbrk(fname, reject);
+        if (c) {
+                fprintf(stderr, "Error: \"%s\" is an invalid filename: rejected character: \"%c\"\n", fname, *c);
+                exit(1);
+        }
+}
+
 // takes string with comma separated int values, returns int array
 int *str_to_int_array(const char *str, size_t *sz) {
         assert(str && sz);