gitweb: No error messages with unescaped/unprotected user input

diff --git a/builtin-apply.c b/builtin-apply.c
index d924ac3d0ab663c2ceb05c2cb9943f6caa23c0ef..f8c6763c7464a01ea81fae0665a7aef50809d031 100644 (file)
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -120,7 +120,7 @@ struct fragment {
 struct patch {
        char *new_name, *old_name, *def_name;
        unsigned int old_mode, new_mode;
-       int is_rename, is_copy, is_new, is_delete, is_binary;
+       int is_rename, is_copy, is_new, is_delete, is_binary, is_reverse;
 #define BINARY_DELTA_DEFLATED 1
 #define BINARY_LITERAL_DEFLATED 2
        unsigned long deflate_origlen;
@@ -1119,6 +1119,34 @@ static int parse_chunk(char *buffer, unsigned long size, struct patch *patch)
        return offset + hdrsize + patchsize;
 }
 
+#define swap(a,b) myswap((a),(b),sizeof(a))
+
+#define myswap(a, b, size) do {                \
+       unsigned char mytmp[size];      \
+       memcpy(mytmp, &a, size);                \
+       memcpy(&a, &b, size);           \
+       memcpy(&b, mytmp, size);                \
+} while (0)
+
+static void reverse_patches(struct patch *p)
+{
+       for (; p; p = p->next) {
+               struct fragment *frag = p->fragments;
+
+               swap(p->new_name, p->old_name);
+               swap(p->new_mode, p->old_mode);
+               swap(p->is_new, p->is_delete);
+               swap(p->lines_added, p->lines_deleted);
+               swap(p->old_sha1_prefix, p->new_sha1_prefix);
+
+               for (; frag; frag = frag->next) {
+                       swap(frag->newpos, frag->oldpos);
+                       swap(frag->newlines, frag->oldlines);
+               }
+               p->is_reverse = !p->is_reverse;
+       }
+}
+
 static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 static const char minuses[]= "----------------------------------------------------------------------";
 
@@ -1336,7 +1364,7 @@ static int apply_line(char *output, const char *patch, int plen)
 }
 
 static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag,
-       int inaccurate_eof)
+       int reverse, int inaccurate_eof)
 {
        int match_beginning, match_end;
        char *buf = desc->buffer;
@@ -1350,6 +1378,7 @@ static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag,
        int pos, lines;
 
        while (size > 0) {
+               char first;
                int len = linelen(patch, size);
                int plen;
 
@@ -1366,16 +1395,23 @@ static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag,
                plen = len-1;
                if (len < size && patch[len] == '\\')
                        plen--;
-               switch (*patch) {
+               first = *patch;
+               if (reverse) {
+                       if (first == '-')
+                               first = '+';
+                       else if (first == '+')
+                               first = '-';
+               }
+               switch (first) {
                case ' ':
                case '-':
                        memcpy(old + oldsize, patch + 1, plen);
                        oldsize += plen;
-                       if (*patch == '-')
+                       if (first == '-')
                                break;
                /* Fall-through for ' ' */
                case '+':
-                       if (*patch != '+' || !no_add)
+                       if (first != '+' || !no_add)
                                newsize += apply_line(new + newsize, patch,
                                                      plen);
                        break;
@@ -1499,6 +1535,12 @@ static int apply_binary_fragment(struct buffer_desc *desc, struct patch *patch)
        void *data;
        void *result;
 
+       /* Binary patch is irreversible */
+       if (patch->is_reverse)
+               return error("cannot reverse-apply a binary patch to '%s'",
+                            patch->new_name
+                            ? patch->new_name : patch->old_name);
+
        data = inflate_it(fragment->patch, fragment->size,
                          patch->deflate_origlen);
        if (!data)
@@ -1615,7 +1657,8 @@ static int apply_fragments(struct buffer_desc *desc, struct patch *patch)
                return apply_binary(desc, patch);
 
        while (frag) {
-               if (apply_one_fragment(desc, frag, patch->inaccurate_eof) < 0)
+               if (apply_one_fragment(desc, frag, patch->is_reverse,
+                                       patch->inaccurate_eof) < 0)
                        return error("patch failed: %s:%ld",
                                     name, frag->oldpos);
                frag = frag->next;
@@ -2142,7 +2185,8 @@ static int use_patch(struct patch *p)
        return 1;
 }
 
-static int apply_patch(int fd, const char *filename, int inaccurate_eof)
+static int apply_patch(int fd, const char *filename,
+               int reverse, int inaccurate_eof)
 {
        unsigned long offset, size;
        char *buffer = read_patch_file(fd, &size);
@@ -2162,6 +2206,8 @@ static int apply_patch(int fd, const char *filename, int inaccurate_eof)
                nr = parse_chunk(buffer + offset, size, patch);
                if (nr < 0)
                        break;
+               if (reverse)
+                       reverse_patches(patch);
                if (use_patch(patch)) {
                        patch_stats(patch);
                        *listp = patch;
@@ -2222,10 +2268,11 @@ static int git_apply_config(const char *var, const char *value)
 }
 
 
-int cmd_apply(int argc, const char **argv, char **envp)
+int cmd_apply(int argc, const char **argv, const char *prefix)
 {
        int i;
        int read_stdin = 1;
+       int reverse = 0;
        int inaccurate_eof = 0;
 
        const char *whitespace_option = NULL;
@@ -2236,7 +2283,7 @@ int cmd_apply(int argc, const char **argv, char **envp)
                int fd;
 
                if (!strcmp(arg, "-")) {
-                       apply_patch(0, "<stdin>", inaccurate_eof);
+                       apply_patch(0, "<stdin>", reverse, inaccurate_eof);
                        read_stdin = 0;
                        continue;
                }
@@ -2313,6 +2360,10 @@ int cmd_apply(int argc, const char **argv, char **envp)
                        parse_whitespace_option(arg + 13);
                        continue;
                }
+               if (!strcmp(arg, "-R") || !strcmp(arg, "--reverse")) {
+                       reverse = 1;
+                       continue;
+               }
                if (!strcmp(arg, "--inaccurate-eof")) {
                        inaccurate_eof = 1;
                        continue;
@@ -2333,12 +2384,12 @@ int cmd_apply(int argc, const char **argv, char **envp)
                        usage(apply_usage);
                read_stdin = 0;
                set_default_whitespace_mode(whitespace_option);
-               apply_patch(fd, arg, inaccurate_eof);
+               apply_patch(fd, arg, reverse, inaccurate_eof);
                close(fd);
        }
        set_default_whitespace_mode(whitespace_option);
        if (read_stdin)
-               apply_patch(0, "<stdin>", inaccurate_eof);
+               apply_patch(0, "<stdin>", reverse, inaccurate_eof);
        if (whitespace_error) {
                if (squelch_whitespace_errors &&
                    squelch_whitespace_errors < whitespace_error) {