Avoid attempting to defererence a NULL pointer to call read_symlink when the
given filesystem does not provide a read_symlink function. This could be
triggered if the calling filesystem had a file marked as a symlink.
This appears possible for HFS and was observed during fuzzing of NTFS.
Signed-off-by: Andrew Hamilton <adham...@gmail.com>
---
grub-core/fs/fshelp.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/grub-core/fs/fshelp.c b/grub-core/fs/fshelp.c
index cb41934b4..a9d24a908 100644
--- a/grub-core/fs/fshelp.c
+++ b/grub-core/fs/fshelp.c
@@ -226,7 +226,10 @@ find_file (char *currpath,
return grub_error (GRUB_ERR_SYMLINK_LOOP,
N_("too deep nesting of symlinks"));
- symlink = read_symlink (ctx->currnode->node);
+ if (read_symlink != NULL)
+ symlink = read_symlink (ctx->currnode->node);
+ else
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("read_symlink is
NULL"));
if (!symlink)
return grub_errno;
--
2.39.5
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