Temporary fix for stack smashing in mailinfo

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-mailinfo.c b/builtin-mailinfo.c
index b558754142b26399df78472b0bb124144dc194da..d7cb11dc0d6339dbea51c89f3cd4966e8f6b4c3d 100644 (file)
--- a/builtin-mailinfo.c
+++ b/builtin-mailinfo.c
@@ -287,12 +287,12 @@ static void cleanup_space(char *buf)
        }
 }
 
-static void decode_header(char *it);
+static void decode_header(char *it, unsigned itsize);
 static char *header[MAX_HDR_PARSED] = {
        "From","Subject","Date",
 };
 
-static int check_header(char *line, char **hdr_data, int overwrite)
+static int check_header(char *line, unsigned linesize, char **hdr_data, int overwrite)
 {
        int i;
 
@@ -305,7 +305,7 @@ static int check_header(char *line, char **hdr_data, int overwrite)
                        /* Unwrap inline B and Q encoding, and optionally
                         * normalize the meta information to utf8.
                         */
-                       decode_header(line + len + 2);
+                       decode_header(line + len + 2, linesize - len - 2);
                        hdr_data[i] = xmalloc(1000 * sizeof(char));
                        if (! handle_header(line, hdr_data[i], len + 2)) {
                                return 1;
@@ -316,14 +316,14 @@ static int check_header(char *line, char **hdr_data, int overwrite)
        /* Content stuff */
        if (!strncasecmp(line, "Content-Type", 12) &&
                line[12] == ':' && isspace(line[12 + 1])) {
-               decode_header(line + 12 + 2);
+               decode_header(line + 12 + 2, linesize - 12 - 2);
                if (! handle_content_type(line)) {
                        return 1;
                }
        }
        if (!strncasecmp(line, "Content-Transfer-Encoding", 25) &&
                line[25] == ':' && isspace(line[25 + 1])) {
-               decode_header(line + 25 + 2);
+               decode_header(line + 25 + 2, linesize - 25 - 2);
                if (! handle_content_transfer_encoding(line)) {
                        return 1;
                }
@@ -432,10 +432,15 @@ static int read_one_header_line(char *line, int sz, FILE *in)
        return 1;
 }
 
-static int decode_q_segment(char *in, char *ot, char *ep, int rfc2047)
+static int decode_q_segment(char *in, char *ot, unsigned otsize, char *ep, int rfc2047)
 {
+       char *otend = ot + otsize;
        int c;
        while ((c = *in++) != 0 && (in <= ep)) {
+               if (ot == otend) {
+                       *--ot = '\0';
+                       return -1;
+               }
                if (c == '=') {
                        int d = *in++;
                        if (d == '\n' || !d)
@@ -451,12 +456,17 @@ static int decode_q_segment(char *in, char *ot, char *ep, int rfc2047)
        return 0;
 }
 
-static int decode_b_segment(char *in, char *ot, char *ep)
+static int decode_b_segment(char *in, char *ot, unsigned otsize, char *ep)
 {
        /* Decode in..ep, possibly in-place to ot */
        int c, pos = 0, acc = 0;
+       char *otend = ot + otsize;
 
        while ((c = *in++) != 0 && (in <= ep)) {
+               if (ot == otend) {
+                       *--ot = '\0';
+                       return -1;
+               }
                if (c == '+')
                        c = 62;
                else if (c == '/')
@@ -518,7 +528,7 @@ static const char *guess_charset(const char *line, const char *target_charset)
        return "latin1";
 }
 
-static void convert_to_utf8(char *line, const char *charset)
+static void convert_to_utf8(char *line, unsigned linesize, const char *charset)
 {
        char *out;
 
@@ -534,11 +544,11 @@ static void convert_to_utf8(char *line, const char *charset)
        if (!out)
                die("cannot convert from %s to %s\n",
                    charset, metainfo_charset);
-       strcpy(line, out);
+       strlcpy(line, out, linesize);
        free(out);
 }
 
-static int decode_header_bq(char *it)
+static int decode_header_bq(char *it, unsigned itsize)
 {
        char *in, *out, *ep, *cp, *sp;
        char outbuf[1000];
@@ -578,56 +588,60 @@ static int decode_header_bq(char *it)
                default:
                        return rfc2047; /* no munging */
                case 'b':
-                       sz = decode_b_segment(cp + 3, piecebuf, ep);
+                       sz = decode_b_segment(cp + 3, piecebuf, sizeof(piecebuf), ep);
                        break;
                case 'q':
-                       sz = decode_q_segment(cp + 3, piecebuf, ep, 1);
+                       sz = decode_q_segment(cp + 3, piecebuf, sizeof(piecebuf), ep, 1);
                        break;
                }
                if (sz < 0)
                        return rfc2047;
                if (metainfo_charset)
-                       convert_to_utf8(piecebuf, charset_q);
+                       convert_to_utf8(piecebuf, sizeof(piecebuf), charset_q);
+
+               sz = strlen(piecebuf);
+               if (outbuf + sizeof(outbuf) <= out + sz)
+                       return rfc2047; /* no munging */
                strcpy(out, piecebuf);
-               out += strlen(out);
+               out += sz;
                in = ep + 2;
        }
        strcpy(out, in);
-       strcpy(it, outbuf);
+       strlcpy(it, outbuf, itsize);
        return rfc2047;
 }
 
-static void decode_header(char *it)
+static void decode_header(char *it, unsigned itsize)
 {
 
-       if (decode_header_bq(it))
+       if (decode_header_bq(it, itsize))
                return;
        /* otherwise "it" is a straight copy of the input.
         * This can be binary guck but there is no charset specified.
         */
        if (metainfo_charset)
-               convert_to_utf8(it, "");
+               convert_to_utf8(it, itsize, "");
 }
 
-static void decode_transfer_encoding(char *line)
+static void decode_transfer_encoding(char *line, unsigned linesize)
 {
        char *ep;
 
        switch (transfer_encoding) {
        case TE_QP:
                ep = line + strlen(line);
-               decode_q_segment(line, line, ep, 0);
+               decode_q_segment(line, line, linesize, ep, 0);
                break;
        case TE_BASE64:
                ep = line + strlen(line);
-               decode_b_segment(line, line, ep);
+               decode_b_segment(line, line, linesize, ep);
                break;
        case TE_DONTCARE:
                break;
        }
 }
 
-static int handle_filter(char *line);
+static int handle_filter(char *line, unsigned linesize);
 
 static int find_boundary(void)
 {
@@ -655,7 +669,7 @@ again:
                                        "can't recover\n");
                        exit(1);
                }
-               handle_filter(newline);
+               handle_filter(newline, sizeof(newline));
 
                /* skip to the next boundary */
                if (!find_boundary())
@@ -670,7 +684,7 @@ again:
 
        /* slurp in this section's info */
        while (read_one_header_line(line, sizeof(line), fin))
-               check_header(line, p_hdr_data, 0);
+               check_header(line, sizeof(line), p_hdr_data, 0);
 
        /* eat the blank line after section info */
        return (fgets(line, sizeof(line), fin) != NULL);
@@ -709,9 +723,10 @@ static inline int patchbreak(const char *line)
 }
 
 
-static int handle_commit_msg(char *line)
+static int handle_commit_msg(char *line, unsigned linesize)
 {
        static int still_looking = 1;
+       char *endline = line + linesize;
 
        if (!cmitmsg)
                return 0;
@@ -726,13 +741,13 @@ static int handle_commit_msg(char *line)
                        if (!*cp)
                                return 0;
                }
-               if ((still_looking = check_header(cp, s_hdr_data, 0)) != 0)
+               if ((still_looking = check_header(cp, endline - cp, s_hdr_data, 0)) != 0)
                        return 0;
        }
 
        /* normalize the log message to UTF-8. */
        if (metainfo_charset)
-               convert_to_utf8(line, charset);
+               convert_to_utf8(line, endline - line, charset);
 
        if (patchbreak(line)) {
                fclose(cmitmsg);
@@ -751,7 +766,7 @@ static int handle_patch(char *line)
        return 0;
 }
 
-static int handle_filter(char *line)
+static int handle_filter(char *line, unsigned linesize)
 {
        static int filter = 0;
 
@@ -760,7 +775,7 @@ static int handle_filter(char *line)
         */
        switch (filter) {
        case 0:
-               if (!handle_commit_msg(line))
+               if (!handle_commit_msg(line, linesize))
                        break;
                filter++;
        case 1:
@@ -792,14 +807,14 @@ static void handle_body(void)
                        /* flush any leftover */
                        if ((transfer_encoding == TE_BASE64)  &&
                            (np != newline)) {
-                               handle_filter(newline);
+                               handle_filter(newline, sizeof(newline));
                        }
                        if (!handle_boundary())
                                return;
                }
 
                /* Unwrap transfer encoding */
-               decode_transfer_encoding(line);
+               decode_transfer_encoding(line, sizeof(line));
 
                switch (transfer_encoding) {
                case TE_BASE64:
@@ -808,7 +823,7 @@ static void handle_body(void)
 
                        /* binary data most likely doesn't have newlines */
                        if (message_type != TYPE_TEXT) {
-                               rc = handle_filter(line);
+                               rc = handle_filter(line, sizeof(newline));
                                break;
                        }
 
@@ -825,7 +840,7 @@ static void handle_body(void)
                                        /* should be sitting on a new line */
                                        *(++np) = 0;
                                        op++;
-                                       rc = handle_filter(newline);
+                                       rc = handle_filter(newline, sizeof(newline));
                                        np = newline;
                                }
                        } while (*op != 0);
@@ -835,7 +850,7 @@ static void handle_body(void)
                        break;
                }
                default:
-                       rc = handle_filter(line);
+                       rc = handle_filter(line, sizeof(newline));
                }
                if (rc)
                        /* nothing left to filter */
@@ -922,7 +937,7 @@ static int mailinfo(FILE *in, FILE *out, int ks, const char *encoding,
 
        /* process the email header */
        while (read_one_header_line(line, sizeof(line), fin))
-               check_header(line, p_hdr_data, 1);
+               check_header(line, sizeof(line), p_hdr_data, 1);
 
        handle_body();
        handle_info();