From fd55a19eb1d49ae54008d932a65f79cd6fda45c9 Mon Sep 17 00:00:00 2001 From: Dmitry Potapov Date: Wed, 16 Jul 2008 18:54:02 +0400 Subject: [PATCH] Fix buffer overflow in git diff If PATH_MAX on your system is smaller than a path stored, it may cause buffer overflow and stack corruption in diff_addremove() and diff_change() functions when running git-diff Signed-off-by: Dmitry Potapov Signed-off-by: Junio C Hamano --- diff-lib.c | 8 ++++---- diff.c | 11 ++--------- diff.h | 9 ++++----- revision.c | 4 ++-- tree-diff.c | 27 ++++++++++++++++++++++----- 5 files changed, 34 insertions(+), 25 deletions(-) diff --git a/diff-lib.c b/diff-lib.c index b17722d66a7008..e7eaff9a68ccbc 100644 --- a/diff-lib.c +++ b/diff-lib.c @@ -171,7 +171,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option) if (silent_on_removed) continue; diff_addremove(&revs->diffopt, '-', ce->ce_mode, - ce->sha1, ce->name, NULL); + ce->sha1, ce->name); continue; } changed = ce_match_stat(ce, &st, ce_option); @@ -184,7 +184,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option) newmode = ce_mode_from_stat(ce, st.st_mode); diff_change(&revs->diffopt, oldmode, newmode, ce->sha1, (changed ? null_sha1 : ce->sha1), - ce->name, NULL); + ce->name); } diffcore_std(&revs->diffopt); @@ -208,7 +208,7 @@ static void diff_index_show_file(struct rev_info *revs, const unsigned char *sha1, unsigned int mode) { diff_addremove(&revs->diffopt, prefix[0], mode, - sha1, ce->name, NULL); + sha1, ce->name); } static int get_stat_data(struct cache_entry *ce, @@ -312,7 +312,7 @@ static int show_modified(struct oneway_unpack_data *cbdata, return 0; diff_change(&revs->diffopt, oldmode, mode, - old->sha1, sha1, old->name, NULL); + old->sha1, sha1, old->name); return 0; } diff --git a/diff.c b/diff.c index 78c4d3a35a975d..386de826d3a050 100644 --- a/diff.c +++ b/diff.c @@ -3356,9 +3356,8 @@ int diff_result_code(struct diff_options *opt, int status) void diff_addremove(struct diff_options *options, int addremove, unsigned mode, const unsigned char *sha1, - const char *base, const char *path) + const char *concatpath) { - char concatpath[PATH_MAX]; struct diff_filespec *one, *two; if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode)) @@ -3380,9 +3379,6 @@ void diff_addremove(struct diff_options *options, addremove = (addremove == '+' ? '-' : addremove == '-' ? '+' : addremove); - if (!path) path = ""; - sprintf(concatpath, "%s%s", base, path); - if (options->prefix && strncmp(concatpath, options->prefix, options->prefix_length)) return; @@ -3403,9 +3399,8 @@ void diff_change(struct diff_options *options, unsigned old_mode, unsigned new_mode, const unsigned char *old_sha1, const unsigned char *new_sha1, - const char *base, const char *path) + const char *concatpath) { - char concatpath[PATH_MAX]; struct diff_filespec *one, *two; if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode) @@ -3418,8 +3413,6 @@ void diff_change(struct diff_options *options, tmp = old_mode; old_mode = new_mode; new_mode = tmp; tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c; } - if (!path) path = ""; - sprintf(concatpath, "%s%s", base, path); if (options->prefix && strncmp(concatpath, options->prefix, options->prefix_length)) diff --git a/diff.h b/diff.h index 5dc0cb595b6486..50fb5ddb0bec02 100644 --- a/diff.h +++ b/diff.h @@ -14,12 +14,12 @@ typedef void (*change_fn_t)(struct diff_options *options, unsigned old_mode, unsigned new_mode, const unsigned char *old_sha1, const unsigned char *new_sha1, - const char *base, const char *path); + const char *fullpath); typedef void (*add_remove_fn_t)(struct diff_options *options, int addremove, unsigned mode, const unsigned char *sha1, - const char *base, const char *path); + const char *fullpath); typedef void (*diff_format_fn_t)(struct diff_queue_struct *q, struct diff_options *options, void *data); @@ -164,14 +164,13 @@ extern void diff_addremove(struct diff_options *, int addremove, unsigned mode, const unsigned char *sha1, - const char *base, - const char *path); + const char *fullpath); extern void diff_change(struct diff_options *, unsigned mode1, unsigned mode2, const unsigned char *sha1, const unsigned char *sha2, - const char *base, const char *path); + const char *fullpath); extern void diff_unmerge(struct diff_options *, const char *path, diff --git a/revision.c b/revision.c index fc667552592daa..8dc3ca7bf696c1 100644 --- a/revision.c +++ b/revision.c @@ -259,7 +259,7 @@ static int tree_difference = REV_TREE_SAME; static void file_add_remove(struct diff_options *options, int addremove, unsigned mode, const unsigned char *sha1, - const char *base, const char *path) + const char *fullpath) { int diff = REV_TREE_DIFFERENT; @@ -285,7 +285,7 @@ static void file_change(struct diff_options *options, unsigned old_mode, unsigned new_mode, const unsigned char *old_sha1, const unsigned char *new_sha1, - const char *base, const char *path) + const char *fullpath) { tree_difference = REV_TREE_DIFFERENT; DIFF_OPT_SET(options, HAS_CHANGES); diff --git a/tree-diff.c b/tree-diff.c index e1e2e6c6ce3c4e..bbb126fc46cfb2 100644 --- a/tree-diff.c +++ b/tree-diff.c @@ -15,6 +15,15 @@ static char *malloc_base(const char *base, int baselen, const char *path, int pa return newbase; } +static char *malloc_fullname(const char *base, int baselen, const char *path, int pathlen) +{ + char *fullname = xmalloc(baselen + pathlen + 1); + memcpy(fullname, base, baselen); + memcpy(fullname + baselen, path, pathlen); + fullname[baselen + pathlen] = 0; + return fullname; +} + static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen); @@ -24,6 +33,7 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const const char *path1, *path2; const unsigned char *sha1, *sha2; int cmp, pathlen1, pathlen2; + char *fullname; sha1 = tree_entry_extract(t1, &path1, &mode1); sha2 = tree_entry_extract(t2, &path2, &mode2); @@ -55,15 +65,20 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) { int retval; char *newbase = malloc_base(base, baselen, path1, pathlen1); - if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) + if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) { + newbase[baselen + pathlen1] = 0; opt->change(opt, mode1, mode2, - sha1, sha2, base, path1); + sha1, sha2, newbase); + newbase[baselen + pathlen1] = '/'; + } retval = diff_tree_sha1(sha1, sha2, newbase, opt); free(newbase); return retval; } - opt->change(opt, mode1, mode2, sha1, sha2, base, path1); + fullname = malloc_fullname(base, baselen, path1, pathlen1); + opt->change(opt, mode1, mode2, sha1, sha2, fullname); + free(fullname); return 0; } @@ -205,10 +220,10 @@ static void show_entry(struct diff_options *opt, const char *prefix, struct tree unsigned mode; const char *path; const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode); + int pathlen = tree_entry_len(path, sha1); if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) { enum object_type type; - int pathlen = tree_entry_len(path, sha1); char *newbase = malloc_base(base, baselen, path, pathlen); struct tree_desc inner; void *tree; @@ -224,7 +239,9 @@ static void show_entry(struct diff_options *opt, const char *prefix, struct tree free(tree); free(newbase); } else { - opt->add_remove(opt, prefix[0], mode, sha1, base, path); + char *fullname = malloc_fullname(base, baselen, path, pathlen); + opt->add_remove(opt, prefix[0], mode, sha1, fullname); + free(fullname); } }