18.08.2015 00:57, dann frazier пишет:
grub_net_fs_open() saves off a copy of the file structure it gets passed and
uses it to create a bufio structure. It then overwrites the passed in file
structure with this new bufio structure. Since file->name doesn't get set
until we return back to grub_file_open(), it means that only the bufio
structure gets a valid file->name. The "real" file's name is left
uninitialized. This leads to a crash when the progress module hook is called
on it. Fix this by adding a copy of the filename during the switcheroo.
Actually name was already saved off as device->net-name. What about
attached patch? I'll commit leak fix separately.
grub_file_close() will free that string in the success case, we only need
to handle the free in an error. While we're at it, also fix a leaked file
structure in the case that grub_strdup() fails when setting
file->device->net->name.
Finally, make progress more robust by checking for NULL before reading the
name. Andrei noticed that this could occur if grub_strdup() fails in
grub_file_open().
Signed-off-by: dann frazier <dann.fraz...@canonical.com>
---
grub-core/lib/progress.c | 3 +--
grub-core/net/net.c | 14 +++++++++++++-
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/grub-core/lib/progress.c b/grub-core/lib/progress.c
index 63a0767..2775554 100644
--- a/grub-core/lib/progress.c
+++ b/grub-core/lib/progress.c
@@ -70,8 +70,7 @@ grub_file_progress_hook_real (grub_disk_addr_t sector
__attribute__ ((unused)),
percent = grub_divmod64 (100 * file->progress_offset,
file->size, 0);
- partial_file_name = grub_strrchr (file->name, '/');
- if (partial_file_name)
+ if (file->name && (partial_file_name = grub_strrchr (file->name, '/')))
partial_file_name++;
else
partial_file_name = "";
diff --git a/grub-core/net/net.c b/grub-core/net/net.c
index 21a4e94..9f83765 100644
--- a/grub-core/net/net.c
+++ b/grub-core/net/net.c
@@ -1391,7 +1391,17 @@ grub_net_fs_open (struct grub_file *file_out, const char
*name)
file->device->net->packs.last = NULL;
file->device->net->name = grub_strdup (name);
if (!file->device->net->name)
- return grub_errno;
+ {
+ grub_free (file);
+ return grub_errno;
+ }
+ file->name = grub_strdup (name);
+ if (!file->name)
+ {
+ grub_free (file->device->net->name);
+ grub_free (file);
+ return grub_errno;
+ }
err = file->device->net->protocol->open (file, name);
if (err)
@@ -1401,6 +1411,7 @@ grub_net_fs_open (struct grub_file *file_out, const char
*name)
grub_netbuff_free (file->device->net->packs.first->nb);
grub_net_remove_packet (file->device->net->packs.first);
}
+ grub_free (file->name);
grub_free (file->device->net->name);
grub_free (file);
return err;
@@ -1414,6 +1425,7 @@ grub_net_fs_open (struct grub_file *file_out, const char
*name)
grub_net_remove_packet (file->device->net->packs.first);
}
file->device->net->protocol->close (file);
+ grub_free (file->name);
grub_free (file->device->net->name);
grub_free (file);
return grub_errno;
From: Andrei Borzenkov <arvidj...@gmail.com>
Subject: [PATCH] progress: avoid NULL dereference for net files
>From original patch by dann frazier <dann.fraz...@canonical.com>:
grub_net_fs_open() saves off a copy of the file structure it gets passed and
uses it to create a bufio structure. It then overwrites the passed in file
structure with this new bufio structure. Since file->name doesn't get set
until we return back to grub_file_open(), it means that only the bufio
structure gets a valid file->name. The "real" file's name is left
uninitialized. This leads to a crash when the progress module hook is called
on it.
grub_net_fs_open() already saved copy of file name as ->net->name, so change
progress module to use it.
Also, grub_file_open may leave file->name as NULL if grub_strdup fails. Check
for it.
Also-By: dann frazier <dann.fraz...@canonical.com>
---
grub-core/lib/progress.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/grub-core/lib/progress.c b/grub-core/lib/progress.c
index 63a0767..7c723eb 100644
--- a/grub-core/lib/progress.c
+++ b/grub-core/lib/progress.c
@@ -23,6 +23,7 @@
#include <grub/dl.h>
#include <grub/misc.h>
#include <grub/normal.h>
+#include <grub/net.h>
GRUB_MOD_LICENSE ("GPLv3+");
@@ -70,7 +71,12 @@ grub_file_progress_hook_real (grub_disk_addr_t sector __attribute__ ((unused)),
percent = grub_divmod64 (100 * file->progress_offset,
file->size, 0);
- partial_file_name = grub_strrchr (file->name, '/');
+ if (file->device->net)
+ partial_file_name = grub_strrchr (file->device->net->name, '/');
+ else if (file->name) /* grub_file_open() may leave it as NULL */
+ partial_file_name = grub_strrchr (file->name, '/');
+ else
+ partial_file_name = NULL;
if (partial_file_name)
partial_file_name++;
else
--
tg: (ba218c1..) u/progress-net-file (depends on: master)
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