Skip to content

Commit

Permalink
env-file: when resolving env vars in command lines, collect list of u…
Browse files Browse the repository at this point in the history 
…nset/invalid ones

When resolving environment variables we currently silently resolve unset
and invalid environment variables to empty strings. Let's do this
slightly less silently: log about unset and invalid env vars, but still
resolve them to an empty string.

Fixes: #27036
  • Loading branch information
@poettering
poettering committed Jun 27, 2023
1 parent 7658139 commit f331434
Show file tree
Hide file tree
Showing 6 changed files with 290 additions and 87 deletions.
13 changes: 7 additions & 6 deletions src/basic/env-file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -525,6 +525,7 @@ static int merge_env_file_push(

char ***env = ASSERT_PTR(userdata);
char *expanded_value;
int r;

assert(key);

Expand All @@ -539,12 +540,12 @@ static int merge_env_file_push(
return 0;
}

expanded_value = replace_env(value, *env,
REPLACE_ENV_USE_ENVIRONMENT|
REPLACE_ENV_ALLOW_BRACELESS|
REPLACE_ENV_ALLOW_EXTENDED);
if (!expanded_value)
return -ENOMEM;
r = replace_env(value,
*env,
REPLACE_ENV_USE_ENVIRONMENT|REPLACE_ENV_ALLOW_BRACELESS|REPLACE_ENV_ALLOW_EXTENDED,
&expanded_value);
if (r < 0)
return log_error_errno(r, "%s:%u: Failed to expand variable '%s': %m", strna(filename), line, value);

free_and_replace(value, expanded_value);

Expand Down
248 changes: 192 additions & 56 deletions src/basic/env-util.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -574,7 +574,61 @@ char **strv_env_clean_with_callback(char **e, void (*invalid_callback)(const cha
return e;
}

char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags flags) {
static int strv_extend_with_length(char ***l, const char *s, size_t n) {
char *c;

c = strndup(s, n);
if (!c)
return -ENOMEM;

return strv_consume(l, c);
}

static int strv_env_get_n_validated(
char **env,
const char *name,
size_t l,
ReplaceEnvFlags flags,
char **ret, /* points into the env block! do not free! */
char ***unset_variables, /* updated in place */
char ***bad_variables) { /* ditto */

char *e;
int r;

assert(l == 0 || name);
assert(ret);

if (env_name_is_valid_n(name, l)) {
e = strv_env_get_n(env, name, l, flags);
if (!e && unset_variables) {
r = strv_extend_with_length(unset_variables, name, l);
if (r < 0)
return r;
}
} else {
e = NULL; /* Resolve invalid variable names the same way as unset ones */

if (bad_variables) {
r = strv_extend_with_length(bad_variables, name, l);
if (r < 0)
return r;
}
}

*ret = e;
return !!e;
}

int replace_env_full(
const char *format,
size_t n,
char **env,
ReplaceEnvFlags flags,
char **ret,
char ***ret_unset_variables,
char ***ret_bad_variables) {

enum {
WORD,
CURLY,
Expand All @@ -585,14 +639,21 @@ char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags fl
ALTERNATE_VALUE,
} state = WORD;

_cleanup_strv_free_ char **unset_variables = NULL, **bad_variables = NULL;
const char *e, *word = format, *test_value = NULL; /* test_value is initialized to appease gcc */
char *k;
_cleanup_free_ char *s = NULL;
char ***pu, ***pb, *k;
size_t i, len = 0; /* len is initialized to appease gcc */
int nest = 0;
int nest = 0, r;

assert(format);

if (n == SIZE_MAX)
n = strlen(format);

pu = ret_unset_variables ? &unset_variables : NULL;
pb = ret_bad_variables ? &bad_variables : NULL;

for (e = format, i = 0; *e && i < n; e ++, i ++)
switch (state) {

Expand All @@ -605,27 +666,28 @@ char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags fl
if (*e == '{') {
k = strnappend(s, word, e-word-1);
if (!k)
return NULL;
return -ENOMEM;

free_and_replace(s, k);

word = e-1;
state = VARIABLE;
nest++;

} else if (*e == '$') {
k = strnappend(s, word, e-word);
if (!k)
return NULL;
return -ENOMEM;

free_and_replace(s, k);

word = e+1;
state = WORD;

} else if (flags & REPLACE_ENV_ALLOW_BRACELESS && strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
} else if (FLAGS_SET(flags, REPLACE_ENV_ALLOW_BRACELESS) && strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
k = strnappend(s, word, e-word-1);
if (!k)
return NULL;
return -ENOMEM;

free_and_replace(s, k);

Expand All @@ -638,12 +700,14 @@ char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags fl

case VARIABLE:
if (*e == '}') {
const char *t;
char *t;

t = strv_env_get_n(env, word+2, e-word-2, flags);
r = strv_env_get_n_validated(env, word+2, e-word-2, flags, &t, pu, pb);
if (r < 0)
return r;

if (!strextend(&s, t))
return NULL;
return -ENOMEM;

word = e+1;
state = WORD;
Expand Down Expand Up @@ -685,18 +749,37 @@ char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags fl

nest--;
if (nest == 0) {
const char *t;
_cleanup_strv_free_ char **u = NULL, **b = NULL;
_cleanup_free_ char *v = NULL;
char *t = NULL;

r = strv_env_get_n_validated(env, word+2, len, flags, &t, pu, pb);
if (r < 0)
return r;

t = strv_env_get_n(env, word+2, len, flags);
if (t && state == ALTERNATE_VALUE) {
r = replace_env_full(test_value, e-test_value, env, flags, &v, pu ? &u : NULL, pb ? &b : NULL);
if (r < 0)
return r;

if (t && state == ALTERNATE_VALUE)
t = v = replace_env_n(test_value, e-test_value, env, flags);
else if (!t && state == DEFAULT_VALUE)
t = v = replace_env_n(test_value, e-test_value, env, flags);
t = v;
} else if (!t && state == DEFAULT_VALUE) {
r = replace_env_full(test_value, e-test_value, env, flags, &v, pu ? &u : NULL, pb ? &b : NULL);
if (r < 0)
return r;

t = v;
}

r = strv_extend_strv(&unset_variables, u, /* filter_duplicates= */ true);
if (r < 0)
return r;
r = strv_extend_strv(&bad_variables, b, /* filter_duplicates= */ true);
if (r < 0)
return r;

if (!strextend(&s, t))
return NULL;
return -ENOMEM;

word = e+1;
state = WORD;
Expand All @@ -707,12 +790,14 @@ char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags fl
assert(flags & REPLACE_ENV_ALLOW_BRACELESS);

if (!strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
const char *t;
char *t = NULL;

t = strv_env_get_n(env, word+1, e-word-1, flags);
r = strv_env_get_n_validated(env, word+1, e-word-1, flags, &t, &unset_variables, &bad_variables);
if (r < 0)
return r;

if (!strextend(&s, t))
return NULL;
return -ENOMEM;

word = e--;
i--;
Expand All @@ -722,74 +807,125 @@ char *replace_env_n(const char *format, size_t n, char **env, ReplaceEnvFlags fl
}

if (state == VARIABLE_RAW) {
const char *t;
char *t;

assert(flags & REPLACE_ENV_ALLOW_BRACELESS);

t = strv_env_get_n(env, word+1, e-word-1, flags);
return strjoin(s, t);
} else
return strnappend(s, word, e-word);
r = strv_env_get_n_validated(env, word+1, e-word-1, flags, &t, &unset_variables, &bad_variables);
if (r < 0)
return r;

if (!strextend(&s, t))
return -ENOMEM;

} else if (!strextendn(&s, word, e-word))
return -ENOMEM;

if (ret_unset_variables)
*ret_unset_variables = TAKE_PTR(unset_variables);
if (ret_bad_variables)
*ret_bad_variables = TAKE_PTR(bad_variables);

if (ret)
*ret = TAKE_PTR(s);

return 0;
}

char **replace_env_argv(char **argv, char **env) {
_cleanup_strv_free_ char **ret = NULL;
int replace_env_argv(
char **argv,
char **env,
char ***ret,
char ***ret_unset_variables,
char ***ret_bad_variables) {

_cleanup_strv_free_ char **n = NULL, **unset_variables = NULL, **bad_variables = NULL;
size_t k = 0, l = 0;
int r;

l = strv_length(argv);

ret = new(char*, l+1);
if (!ret)
return NULL;
n = new(char*, l+1);
if (!n)
return -ENOMEM;

STRV_FOREACH(i, argv) {
const char *word = *i;

/* If $FOO appears as single word, replace it by the split up variable */
if ((*i)[0] == '$' && !IN_SET((*i)[1], '{', '$')) {
char *e;
char **w;
if (word[0] == '$' && !IN_SET(word[1], '{', '$')) {
_cleanup_strv_free_ char **m = NULL;
const char *name = word + 1;
char *e, **w;
size_t q;

e = strv_env_get(env, *i+1);
if (e) {
int r;

r = strv_split_full(&m, e, WHITESPACE, EXTRACT_RELAX|EXTRACT_UNQUOTE);
if (r < 0) {
ret[k] = NULL;
return NULL;
}
}
if (env_name_is_valid(name)) {
e = strv_env_get(env, name);
if (e)
r = strv_split_full(&m, e, WHITESPACE, EXTRACT_RELAX|EXTRACT_UNQUOTE);
else if (ret_unset_variables)
r = strv_extend(&unset_variables, name);
else
r = 0;
} else if (ret_bad_variables)
r = strv_extend(&bad_variables, name);
else
r = 0;
if (r < 0)
return r;

q = strv_length(m);
l = l + q - 1;

w = reallocarray(ret, l + 1, sizeof(char *));
if (!w) {
ret[k] = NULL;
return NULL;
}
w = reallocarray(n, l + 1, sizeof(char*));
if (!w)
return -ENOMEM;

ret = w;
n = w;
if (m) {
memcpy(ret + k, m, q * sizeof(char*));
memcpy(n + k, m, (q + 1) * sizeof(char*));
m = mfree(m);
}

k += q;
continue;
}

_cleanup_strv_free_ char **u = NULL, **b = NULL;

/* If ${FOO} appears as part of a word, replace it by the variable as-is */
ret[k] = replace_env(*i, env, 0);
if (!ret[k])
return NULL;
k++;
r = replace_env_full(
word,
/* length= */ SIZE_MAX,
env,
/* flags= */ 0,
n + k,
ret_unset_variables ? &u : NULL,
ret_bad_variables ? &b : NULL);
if (r < 0)
return r;
n[++k] = NULL;

r = strv_extend_strv(&unset_variables, u, /* filter_duplicates= */ true);
if (r < 0)
return r;

r = strv_extend_strv(&bad_variables, b, /*filter_duplicates= */ true);
if (r < 0)
return r;
}

ret[k] = NULL;
return TAKE_PTR(ret);
if (ret_unset_variables) {
strv_uniq(strv_sort(unset_variables));
*ret_unset_variables = TAKE_PTR(unset_variables);
}
if (ret_bad_variables) {
strv_uniq(strv_sort(bad_variables));
*ret_bad_variables = TAKE_PTR(bad_variables);
}

*ret = TAKE_PTR(n);
return 0;
}

int getenv_bool(const char *p) {
Expand Down
Loading

0 comments on commit f331434

Please sign in to comment.