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fileio: if we try to read a file larger than SIZE_MAX this is not a problem if a max_size is specified

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i.e. 32bit userspace reading /proc/kcore on a 64bit kernel with max_size
should not needlessly fail.
This commit is contained in:
Lennart Poettering
2021-05-21 21:54:19 +02:00
parent 0557680919
commit 1b5e91a8d2
1 changed files with 11 additions and 5 deletions
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src/basic/fileio.c
+11 -5
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@@ -405,12 +405,18 @@ int read_virtual_file(const char *filename, size_t max_size, char **ret_contents
/* Be prepared for files from /proc which generally report a file size of 0. */
assert_cc(READ_FULL_BYTES_MAX < SSIZE_MAX);
if (st.st_size > 0) {
if (st.st_size > SSIZE_MAX) /* Avoid overflow with 32-bit size_t and 64-bit off_t. */
return -EFBIG;
if (st.st_size > SSIZE_MAX) { /* Avoid overflow with 32-bit size_t and 64-bit off_t. */
size = MIN((size_t) st.st_size, max_size);
if (size > READ_FULL_BYTES_MAX)
return -EFBIG;
if (max_size == SIZE_MAX)
return -EFBIG;
size = max_size;
} else {
size = MIN((size_t) st.st_size, max_size);
if (size > READ_FULL_BYTES_MAX)
return -EFBIG;
}
n_retries--;
} else {