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Make file-reading and key-reading preserve errno

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This is an important part of #16582.
This commit is contained in:
Nick Mathewson 2015-07-14 10:18:52 -04:00
parent b06759edfd
commit b566cb9e84
2 changed files with 21 additions and 5 deletions
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21
src/common/crypto_curve25519.c
View File

@ -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 * <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 * 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 * 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 ssize_t
crypto_read_tagged_contents_from_file(const char *fname, crypto_read_tagged_contents_from_file(const char *fname,
const char *typestring, const char *typestring,
@ -214,27 +214,36 @@ crypto_read_tagged_contents_from_file(const char *fname,
struct stat st; struct stat st;
ssize_t r = -1; ssize_t r = -1;
size_t st_size = 0; size_t st_size = 0;
int saved_errno = 0;
*tag_out = NULL; *tag_out = NULL;
st.st_size = 0; st.st_size = 0;
content = read_file_to_str(fname, RFTS_BIN|RFTS_IGNORE_MISSING, &st); content = read_file_to_str(fname, RFTS_BIN|RFTS_IGNORE_MISSING, &st);
if (! content) if (! content) {
saved_errno = errno;
goto end; 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; goto end;
}
st_size = (size_t)st.st_size; st_size = (size_t)st.st_size;
memcpy(prefix, content, 32); memcpy(prefix, content, 32);
prefix[32] = 0; prefix[32] = 0;
/* Check type, extract tag. */ /* Check type, extract tag. */
if (strcmpstart(prefix, "== ") || strcmpend(prefix, " ==") || 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; goto end;
}
if (strcmpstart(prefix+3, typestring) || if (strcmpstart(prefix+3, typestring) ||
3+strlen(typestring) >= 32 || 3+strlen(typestring) >= 32 ||
strcmpstart(prefix+3+strlen(typestring), ": ")) strcmpstart(prefix+3+strlen(typestring), ": ")) {
saved_errno = EINVAL;
goto end; goto end;
}
*tag_out = tor_strndup(prefix+5+strlen(typestring), *tag_out = tor_strndup(prefix+5+strlen(typestring),
strlen(prefix)-8-strlen(typestring)); strlen(prefix)-8-strlen(typestring));
@ -246,6 +255,8 @@ crypto_read_tagged_contents_from_file(const char *fname,
if (content) if (content)
memwipe(content, 0, st_size); memwipe(content, 0, st_size);
tor_free(content); tor_free(content);
if (saved_errno)
errno = saved_errno;
return r; return r;
} }

5
src/common/util.c
View File

@ -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); string = tor_realloc(string, string_max);
r = read(fd, string + pos, string_max - pos - 1); r = read(fd, string + pos, string_max - pos - 1);
if (r < 0) { if (r < 0) {
int save_errno = errno;
tor_free(string); tor_free(string);
errno = save_errno;
return NULL; 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)) { if (S_ISFIFO(statbuf.st_mode)) {
size_t sz = 0; size_t sz = 0;
string = read_file_to_str_until_eof(fd, FIFO_READ_MAX, &sz); string = read_file_to_str_until_eof(fd, FIFO_READ_MAX, &sz);
int save_errno = errno;
if (string && stat_out) { if (string && stat_out) {
statbuf.st_size = sz; statbuf.st_size = sz;
memcpy(stat_out, &statbuf, sizeof(struct stat)); memcpy(stat_out, &statbuf, sizeof(struct stat));
} }
close(fd); close(fd);
if (!string)
errno = save_errno;
return string; return string;
} }
#endif #endif