Commit b566cb9e authored by Nick Mathewson's avatar Nick Mathewson 🎨
Browse files

Make file-reading and key-reading preserve errno

This is an important part of #16582.
parent b06759ed
......@@ -201,7 +201,7 @@ crypto_write_tagged_contents_to_file(const char *fname,
* <b>data_out_len</b>-byte buffer in <b>data_out</b>. Check that the
* typestring matches <b>typestring</b>; store the tag into a newly allocated
* string in <b>tag_out</b>. Return -1 on failure, and the number of bytes of
* data on success. */
* data on success. Preserves the errno from reading the file. */
ssize_t
crypto_read_tagged_contents_from_file(const char *fname,
const char *typestring,
......@@ -214,27 +214,36 @@ crypto_read_tagged_contents_from_file(const char *fname,
struct stat st;
ssize_t r = -1;
size_t st_size = 0;
int saved_errno = 0;
*tag_out = NULL;
st.st_size = 0;
content = read_file_to_str(fname, RFTS_BIN|RFTS_IGNORE_MISSING, &st);
if (! content)
if (! content) {
saved_errno = errno;
goto end;
if (st.st_size < 32 || st.st_size > 32 + data_out_len)
}
if (st.st_size < 32 || st.st_size > 32 + data_out_len) {
saved_errno = EINVAL;
goto end;
}
st_size = (size_t)st.st_size;
memcpy(prefix, content, 32);
prefix[32] = 0;
/* Check type, extract tag. */
if (strcmpstart(prefix, "== ") || strcmpend(prefix, " ==") ||
! tor_mem_is_zero(prefix+strlen(prefix), 32-strlen(prefix)))
! tor_mem_is_zero(prefix+strlen(prefix), 32-strlen(prefix))) {
saved_errno = EINVAL;
goto end;
}
if (strcmpstart(prefix+3, typestring) ||
3+strlen(typestring) >= 32 ||
strcmpstart(prefix+3+strlen(typestring), ": "))
strcmpstart(prefix+3+strlen(typestring), ": ")) {
saved_errno = EINVAL;
goto end;
}
*tag_out = tor_strndup(prefix+5+strlen(typestring),
strlen(prefix)-8-strlen(typestring));
......@@ -246,6 +255,8 @@ crypto_read_tagged_contents_from_file(const char *fname,
if (content)
memwipe(content, 0, st_size);
tor_free(content);
if (saved_errno)
errno = saved_errno;
return r;
}
......
......@@ -2571,7 +2571,9 @@ read_file_to_str_until_eof(int fd, size_t max_bytes_to_read, size_t *sz_out)
string = tor_realloc(string, string_max);
r = read(fd, string + pos, string_max - pos - 1);
if (r < 0) {
int save_errno = errno;
tor_free(string);
errno = save_errno;
return NULL;
}
......@@ -2639,11 +2641,14 @@ read_file_to_str(const char *filename, int flags, struct stat *stat_out)
if (S_ISFIFO(statbuf.st_mode)) {
size_t sz = 0;
string = read_file_to_str_until_eof(fd, FIFO_READ_MAX, &sz);
int save_errno = errno;
if (string && stat_out) {
statbuf.st_size = sz;
memcpy(stat_out, &statbuf, sizeof(struct stat));
}
close(fd);
if (!string)
errno = save_errno;
return string;
}
#endif
......
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