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chase-symlinks: avoid using stack allocation for potentially huge paths

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let's better be safe and use heap allocation for paths which might be
unbounded.

In particular as previously we copied the stack memory to heap anyway,
via a noop path_make_absolute_cwd() call.
This commit is contained in:
Lennart Poettering
2022-04-12 15:41:48 +02:00
parent 8f47f880a4
commit 7b9be862c7
1 changed files with 12 additions and 8 deletions
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20
src/basic/chase-symlinks.c
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@@ -84,6 +84,10 @@ int chase_symlinks(
if (isempty(path))
return -EINVAL;
/* We don't support relative paths in combination with a root directory */
if (FLAGS_SET(flags, CHASE_PREFIX_ROOT) && !path_is_absolute(path))
return -EINVAL;
/* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following
* symlinks relative to a root directory, instead of the root of the host.
*
@@ -161,17 +165,17 @@ int chase_symlinks(
path_simplify(root);
if (flags & CHASE_PREFIX_ROOT) {
/* We don't support relative paths in combination with a root directory */
if (!path_is_absolute(path))
return -EINVAL;
path = prefix_roota(root, path);
buffer = path_join(root, path);
if (!buffer)
return -ENOMEM;
}
}
r = path_make_absolute_cwd(path, &buffer);
if (r < 0)
return r;
if (!buffer) {
r = path_make_absolute_cwd(path, &buffer);
if (r < 0)
return r;
}
fd = open(root ?: "/", O_CLOEXEC|O_DIRECTORY|O_PATH);
if (fd < 0)