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Merge branch 'tb/config-copy-or-rename-in-file-injection'
Avoids issues with renaming or deleting sections with long lines, where
configuration values may be interpreted as sections, leading to
configuration injection. Addresses CVE-2023-29007.

* tb/config-copy-or-rename-in-file-injection:
  config.c: disallow overly-long lines in `copy_or_rename_section_in_file()`
  config.c: avoid integer truncation in `copy_or_rename_section_in_file()`
  config: avoid fixed-sized buffer when renaming/deleting a section
  t1300: demonstrate failure when renaming sections with long lines

Signed-off-by: Taylor Blau <me@ttaylorr.com>
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ttaylorr authored and dscho committed Apr 17, 2023
2 parents 4fe5d0b + 3bb3d6b commit 528290f
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Showing 2 changed files with 55 additions and 11 deletions.
36 changes: 25 additions & 11 deletions config.c
Expand Up @@ -3027,9 +3027,10 @@ void git_config_set_multivar(const char *key, const char *value,
flags);
}

static int section_name_match (const char *buf, const char *name)
static size_t section_name_match (const char *buf, const char *name)
{
int i = 0, j = 0, dot = 0;
size_t i = 0, j = 0;
int dot = 0;
if (buf[i] != '[')
return 0;
for (i = 1; buf[i] && buf[i] != ']'; i++) {
Expand Down Expand Up @@ -3082,6 +3083,8 @@ static int section_name_is_ok(const char *name)
return 1;
}

#define GIT_CONFIG_MAX_LINE_LEN (512 * 1024)

/* if new_name == NULL, the section is removed instead */
static int git_config_copy_or_rename_section_in_file(const char *config_filename,
const char *old_name,
Expand All @@ -3091,11 +3094,12 @@ static int git_config_copy_or_rename_section_in_file(const char *config_filename
char *filename_buf = NULL;
struct lock_file lock = LOCK_INIT;
int out_fd;
char buf[1024];
struct strbuf buf = STRBUF_INIT;
FILE *config_file = NULL;
struct stat st;
struct strbuf copystr = STRBUF_INIT;
struct config_store_data store;
uint32_t line_nr = 0;

memset(&store, 0, sizeof(store));

Expand Down Expand Up @@ -3132,16 +3136,25 @@ static int git_config_copy_or_rename_section_in_file(const char *config_filename
goto out;
}

while (fgets(buf, sizeof(buf), config_file)) {
unsigned i;
int length;
while (!strbuf_getwholeline(&buf, config_file, '\n')) {
size_t i, length;
int is_section = 0;
char *output = buf;
for (i = 0; buf[i] && isspace(buf[i]); i++)
char *output = buf.buf;

line_nr++;

if (buf.len >= GIT_CONFIG_MAX_LINE_LEN) {
ret = error(_("refusing to work with overly long line "
"in '%s' on line %"PRIuMAX),
config_filename, (uintmax_t)line_nr);
goto out;
}

for (i = 0; buf.buf[i] && isspace(buf.buf[i]); i++)
; /* do nothing */
if (buf[i] == '[') {
if (buf.buf[i] == '[') {
/* it's a section */
int offset;
size_t offset;
is_section = 1;

/*
Expand All @@ -3158,7 +3171,7 @@ static int git_config_copy_or_rename_section_in_file(const char *config_filename
strbuf_reset(&copystr);
}

offset = section_name_match(&buf[i], old_name);
offset = section_name_match(&buf.buf[i], old_name);
if (offset > 0) {
ret++;
if (new_name == NULL) {
Expand Down Expand Up @@ -3233,6 +3246,7 @@ static int git_config_copy_or_rename_section_in_file(const char *config_filename
out_no_rollback:
free(filename_buf);
config_store_data_clear(&store);
strbuf_release(&buf);
return ret;
}

Expand Down
30 changes: 30 additions & 0 deletions t/t1300-config.sh
Expand Up @@ -613,6 +613,36 @@ test_expect_success 'renaming to bogus section is rejected' '
test_must_fail git config --rename-section branch.zwei "bogus name"
'

test_expect_success 'renaming a section with a long line' '
{
printf "[b]\\n" &&
printf " c = d %1024s [a] e = f\\n" " " &&
printf "[a] g = h\\n"
} >y &&
git config -f y --rename-section a xyz &&
test_must_fail git config -f y b.e
'

test_expect_success 'renaming an embedded section with a long line' '
{
printf "[b]\\n" &&
printf " c = d %1024s [a] [foo] e = f\\n" " " &&
printf "[a] g = h\\n"
} >y &&
git config -f y --rename-section a xyz &&
test_must_fail git config -f y foo.e
'

test_expect_success 'renaming a section with an overly-long line' '
{
printf "[b]\\n" &&
printf " c = d %525000s e" " " &&
printf "[a] g = h\\n"
} >y &&
test_must_fail git config -f y --rename-section a xyz 2>err &&
test_i18ngrep "refusing to work with overly long line in .y. on line 2" err
'

cat >> .git/config << EOF
[branch "zwei"] a = 1 [branch "vier"]
EOF
Expand Down

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