clamdscan: perform real-path checks in clamd

This patch relocates the real-path check from clamdscan and clamonacc
to clamd. While clamonacc is unlikely to send directories or symlinks
to be scanned, clamdscan may send directories. Real-path checks have
to be performed on the files, not the directories -- both because the
directories may contain symlinks and because the cli_realpath()
function wasn't written to support directories on Windows.

clamd/scanner.c

@@ -133,13 +133,25 @@ void clamd_virus_found_cb(int fd, const char *virname, void *ctx)
 }
 
 #define BUFFSIZE 1024
-int scan_callback(STATBUF *sb, char *filename, const char *msg, enum cli_ftw_reason reason, struct cli_ftw_cbdata *data)
+cl_error_t scan_callback(STATBUF *sb, char *filename, const char *msg, enum cli_ftw_reason reason, struct cli_ftw_cbdata *data)
 {
     struct scan_cb_data *scandata = data->data;
     const char *virname           = NULL;
     int ret;
     int type = scandata->type;
     struct cb_context context;
+    char *real_filename = NULL;
+
+    if (NULL != filename) {
+        if (CL_SUCCESS != cli_realpath((const char *)filename, &real_filename)) {
+            conn_reply_errno(scandata->conn, msg, "real-path check failed:");
+            logg("^Failed to determine real path for: %s\n", filename);
+            scandata->errors++;
+            return CL_SUCCESS;
+        }
+        free(filename);
+        filename = real_filename;
+    }
 
     /* detect disconnected socket,
      * this should NOT detect half-shutdown sockets (SHUT_WR) */
@@ -190,8 +202,8 @@ int scan_callback(STATBUF *sb, char *filename, const char *msg, enum cli_ftw_rea
             break;
     }
 
-        /* check whether the file is excluded */
 #ifdef C_LINUX
+    /* check whether the file is excluded */
     if (procdev && sb && (sb->st_dev == procdev)) {
         free(filename);
         return CL_SUCCESS;

clamd/scanner.h

@@ -63,7 +63,7 @@ struct cb_context {
 
 int scanfd(const client_conn_t *conn, unsigned long int *scanned, const struct cl_engine *engine, struct cl_scan_options *options, const struct optstruct *opts, int odesc, int stream);
 int scanstream(int odesc, unsigned long int *scanned, const struct cl_engine *engine, struct cl_scan_options *options, const struct optstruct *opts, char term);
-int scan_callback(STATBUF *sb, char *filename, const char *msg, enum cli_ftw_reason reason, struct cli_ftw_cbdata *data);
+cl_error_t scan_callback(STATBUF *sb, char *filename, const char *msg, enum cli_ftw_reason reason, struct cli_ftw_cbdata *data);
 int scan_pathchk(const char *path, struct cli_ftw_cbdata *data);
 void hash_callback(int fd, unsigned long long size, const unsigned char *md5, const char *virname, void *ctx);
 void msg_callback(enum cl_msg severity, const char *fullmsg, const char *msg, void *ctx);

clamdscan/proto.c

@@ -262,18 +262,8 @@ int dsresult(int sockd, int scantype, const char *filename, int *printok, int *e
     char *bol, *eol;
     struct RCVLN rcv;
     STATBUF sb;
-    cl_error_t ret;
-    char *real_filename = NULL;
 
     if (filename) {
-        ret = cli_realpath((const char *)filename, &real_filename);
-        if (CL_SUCCESS != ret) {
-            logg("Failed to determine real filename of %s.\n", filename);
-            infected = -1;
-            goto done;
-        }
-        filename = real_filename;
-
         if (1 == chkpath(filename)) {
             goto done;
         }
@@ -408,9 +398,6 @@ int dsresult(int sockd, int scantype, const char *filename, int *printok, int *e
     }
 
 done:
-    if (NULL != real_filename) {
-        free(real_filename);
-    }
     return infected;
 }
 

clamonacc/client/protocol.c

@@ -195,26 +195,6 @@ int onas_dsresult(CURL *curl, int scantype, uint64_t maxstream, const char *file
 
     onas_recvlninit(&rcv, curl);
 
-    cl_error_t ret;
-    char *real_filename = NULL;
-
-    if (filename) {
-        ret = cli_realpath((const char *)filename, &real_filename);
-        if (CL_SUCCESS != ret) {
-            logg("Failed to determine real filename of %s.\n", filename);
-            if (ret_code) {
-                *ret_code = CL_EACCES;
-            }
-            infected = -1;
-            goto done;
-        }
-        filename = real_filename;
-    }
-
-    if (ret_code) {
-        *ret_code = CL_SUCCESS;
-    }
-
     switch (scantype) {
         case MULTI:
         case CONT:
@@ -427,8 +407,5 @@ int onas_dsresult(CURL *curl, int scantype, uint64_t maxstream, const char *file
     }
 
 done:
-    if (NULL != real_filename) {
-        free(real_filename);
-    }
     return infected;
 }

libclamav/others_common.c

@@ -530,9 +530,9 @@ static int get_filetype(const char *fname, int flags, int need_stat,
 
         if ((flags & FOLLOW_SYMLINK_MASK) != FOLLOW_SYMLINK_MASK) {
             /* Following only one of directory/file symlinks, or none, may
-	     * need to lstat.
-	     * If we're following both file and directory symlinks, we don't need
-	     * to lstat(), we can just stat() directly.*/
+	         * need to lstat.
+	         * If we're following both file and directory symlinks, we don't need
+	         * to lstat(), we can just stat() directly.*/
             if (*ft != ft_link) {
                 /* need to lstat to determine if it is a symlink */
                 if (LSTAT(fname, statbuf) == -1)
@@ -563,7 +563,7 @@ static int get_filetype(const char *fname, int flags, int need_stat,
         if (S_ISDIR(statbuf->st_mode) &&
             (*ft != ft_link || (flags & CLI_FTW_FOLLOW_DIR_SYMLINK))) {
             /* A directory, or (a symlink to a directory and we're following dir
-	     * symlinks) */
+	         * symlinks) */
             *ft = ft_directory;
         } else if (S_ISREG(statbuf->st_mode) &&
                    (*ft != ft_link || (flags & CLI_FTW_FOLLOW_FILE_SYMLINK))) {
@@ -622,7 +622,7 @@ int cli_ftw(char *path, int flags, int maxdepth, cli_ftw_cb callback, struct cli
     if (((flags & CLI_FTW_TRIM_SLASHES) || pathchk) && path[0] && path[1]) {
         char *pathend;
         /* trim slashes so that dir and dir/ behave the same when
-	 * they are symlinks, and we are not following symlinks */
+	     * they are symlinks, and we are not following symlinks */
 #ifndef _WIN32
         while (path[0] == *PATHSEP && path[1] == *PATHSEP) path++;
 #endif
@@ -683,7 +683,7 @@ static int cli_ftw_dir(const char *dirname, int flags, int maxdepth, cli_ftw_cb
                 case DT_LNK:
                     if (!(flags & FOLLOW_SYMLINK_MASK)) {
                         /* we don't follow symlinks, don't bother
-			 * stating it */
+			             * stating it */
                         errno = 0;
                         continue;
                     }