mailinfo: fix pointential memory leak if `decode_header` failed

In mailinfo.c:decode_header, if convert_to_utf8 failed, the strbuf stored
in dec will leak. Simply add strbuf_release and free(dec) will solve
this problem.

Signed-off-by: Lidong Yan <502024330056@smail.nju.edu.cn>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/mailinfo.c b/mailinfo.c
index 7b001fa5dbd685cbe2b51c880e961e68461bef31..ee4597da6bef97007b79fb659f19f1b0278e5cf4 100644 (file)
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -381,12 +381,12 @@ static int is_format_patch_separator(const char *line, int len)
        return !memcmp(SAMPLE + (cp - line), cp, strlen(SAMPLE) - (cp - line));
 }
 
-static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
+static int decode_q_segment(struct strbuf *out, const struct strbuf *q_seg,
+                           int rfc2047)
 {
        const char *in = q_seg->buf;
        int c;
-       struct strbuf *out = xmalloc(sizeof(struct strbuf));
-       strbuf_init(out, q_seg->len);
+       strbuf_grow(out, q_seg->len);
 
        while ((c = *in++) != 0) {
                if (c == '=') {
@@ -405,16 +405,15 @@ static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
                        c = 0x20;
                strbuf_addch(out, c);
        }
-       return out;
+       return 0;
 }
 
-static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
+static int decode_b_segment(struct strbuf *out, const struct strbuf *b_seg)
 {
        /* Decode in..ep, possibly in-place to ot */
        int c, pos = 0, acc = 0;
        const char *in = b_seg->buf;
-       struct strbuf *out = xmalloc(sizeof(struct strbuf));
-       strbuf_init(out, b_seg->len);
+       strbuf_grow(out, b_seg->len);
 
        while ((c = *in++) != 0) {
                if (c == '+')
@@ -447,7 +446,7 @@ static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
                        break;
                }
        }
-       return out;
+       return 0;
 }
 
 static int convert_to_utf8(struct mailinfo *mi,
@@ -475,7 +474,7 @@ static int convert_to_utf8(struct mailinfo *mi,
 static void decode_header(struct mailinfo *mi, struct strbuf *it)
 {
        char *in, *ep, *cp;
-       struct strbuf outbuf = STRBUF_INIT, *dec;
+       struct strbuf outbuf = STRBUF_INIT, dec = STRBUF_INIT;
        struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
        int found_error = 1; /* pessimism */
 
@@ -530,18 +529,19 @@ static void decode_header(struct mailinfo *mi, struct strbuf *it)
                default:
                        goto release_return;
                case 'b':
-                       dec = decode_b_segment(&piecebuf);
+                       if ((found_error = decode_b_segment(&dec, &piecebuf)))
+                               goto release_return;
                        break;
                case 'q':
-                       dec = decode_q_segment(&piecebuf, 1);
+                       if ((found_error = decode_q_segment(&dec, &piecebuf, 1)))
+                               goto release_return;
                        break;
                }
-               if (convert_to_utf8(mi, dec, charset_q.buf))
+               if (convert_to_utf8(mi, &dec, charset_q.buf))
                        goto release_return;
 
-               strbuf_addbuf(&outbuf, dec);
-               strbuf_release(dec);
-               free(dec);
+               strbuf_addbuf(&outbuf, &dec);
+               strbuf_release(&dec);
                in = ep + 2;
        }
        strbuf_addstr(&outbuf, in);
@@ -552,6 +552,7 @@ release_return:
        strbuf_release(&outbuf);
        strbuf_release(&charset_q);
        strbuf_release(&piecebuf);
+       strbuf_release(&dec);
 
        if (found_error)
                mi->input_error = -1;
@@ -634,23 +635,22 @@ static int is_inbody_header(const struct mailinfo *mi,
 
 static void decode_transfer_encoding(struct mailinfo *mi, struct strbuf *line)
 {
-       struct strbuf *ret;
+       struct strbuf ret = STRBUF_INIT;
 
        switch (mi->transfer_encoding) {
        case TE_QP:
-               ret = decode_q_segment(line, 0);
+               decode_q_segment(&ret, line, 0);
                break;
        case TE_BASE64:
-               ret = decode_b_segment(line);
+               decode_b_segment(&ret, line);
                break;
        case TE_DONTCARE:
        default:
                return;
        }
        strbuf_reset(line);
-       strbuf_addbuf(line, ret);
-       strbuf_release(ret);
-       free(ret);
+       strbuf_addbuf(line, &ret);
+       strbuf_release(&ret);
 }
 
 static inline int patchbreak(const struct strbuf *line)