[U-Boot] [PATCH] fs: ext4: fix crash on ext4ls
Found a crash while issuing ext4ls with a non-existent directory. Crash test:
=> ext4ls mmc 0 1 ** Can not find directory. ** data abort pc : [<3fd7c2ec>] lr : [<3fd93ed8>] reloc pc : [<26f142ec>] lr : [<26f2bed8>] sp : 3f963338 ip : 3fdc3dc4 fp : 3fd6b370 r10: 00000004 r9 : 3f967ec0 r8 : 3f96db68 r7 : 3fdc99b4 r6 : 00000000 r5 : 3f96dc88 r4 : 3fdcbc8c r3 : fffffffa r2 : 00000000 r1 : 3f96e0bc r0 : 00000002 Flags: nZCv IRQs off FIQs off Mode SVC_32 Resetting CPU ...
resetting ...
Tested on SAMA5D2_Xplained board (sama5d2_xplained_mmc_defconfig)
Looks like crash is introduced by commit: "fa9ca8a" fs/ext4/ext4fs.c: Free dirnode in error path of ext4fs_ls
Issue is that dirnode is not initialized, and then freed if the call to ext4_ls fails. ext4_ls will not change the value of dirnode in this case thus we have a crash with data abort.
I added initialization and a check for dirname being NULL.
Fixes: "fa9ca8a" fs/ext4/ext4fs.c: Free dirnode in error path of ext4fs_ls Cc: Stefan Brüns stefan.bruens@rwth-aachen.de Cc: Tom Rini trini@konsulko.com Signed-off-by: Eugen Hristev eugen.hristev@microchip.com --- Hello,
Regarding this fix, I am not sure if we actually need to free the node, but according to commit "fa9ca8a" , it was added to fix Coverity case. So, I decided to keep the free call under if statement if variable is NULL. If a different fix is required, please advise and I can change and resend.
Thanks !
fs/ext4/ext4fs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c index 4b36a3e..2a28031 100644 --- a/fs/ext4/ext4fs.c +++ b/fs/ext4/ext4fs.c @@ -164,7 +164,7 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
int ext4fs_ls(const char *dirname) { - struct ext2fs_node *dirnode; + struct ext2fs_node *dirnode = NULL; int status;
if (dirname == NULL) @@ -174,7 +174,8 @@ int ext4fs_ls(const char *dirname) FILETYPE_DIRECTORY); if (status != 1) { printf("** Can not find directory. **\n"); - ext4fs_free_node(dirnode, &ext4fs_root->diropen); + if (dirnode) + ext4fs_free_node(dirnode, &ext4fs_root->diropen); return 1; }
On Wed, May 09, 2018 at 12:57:35PM +0300, Eugen Hristev wrote:
Found a crash while issuing ext4ls with a non-existent directory. Crash test:
=> ext4ls mmc 0 1 ** Can not find directory. ** data abort pc : [<3fd7c2ec>] lr : [<3fd93ed8>] reloc pc : [<26f142ec>] lr : [<26f2bed8>] sp : 3f963338 ip : 3fdc3dc4 fp : 3fd6b370 r10: 00000004 r9 : 3f967ec0 r8 : 3f96db68 r7 : 3fdc99b4 r6 : 00000000 r5 : 3f96dc88 r4 : 3fdcbc8c r3 : fffffffa r2 : 00000000 r1 : 3f96e0bc r0 : 00000002 Flags: nZCv IRQs off FIQs off Mode SVC_32 Resetting CPU ...
resetting ...
Tested on SAMA5D2_Xplained board (sama5d2_xplained_mmc_defconfig)
Looks like crash is introduced by commit: "fa9ca8a" fs/ext4/ext4fs.c: Free dirnode in error path of ext4fs_ls
Issue is that dirnode is not initialized, and then freed if the call to ext4_ls fails. ext4_ls will not change the value of dirnode in this case thus we have a crash with data abort.
I added initialization and a check for dirname being NULL.
Fixes: "fa9ca8a" fs/ext4/ext4fs.c: Free dirnode in error path of ext4fs_ls Cc: Stefan Brüns stefan.bruens@rwth-aachen.de Cc: Tom Rini trini@konsulko.com Signed-off-by: Eugen Hristev eugen.hristev@microchip.com
Hello,
Regarding this fix, I am not sure if we actually need to free the node, but according to commit "fa9ca8a" , it was added to fix Coverity case. So, I decided to keep the free call under if statement if variable is NULL. If a different fix is required, please advise and I can change and resend.
Thanks !
fs/ext4/ext4fs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c index 4b36a3e..2a28031 100644 --- a/fs/ext4/ext4fs.c +++ b/fs/ext4/ext4fs.c @@ -164,7 +164,7 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
int ext4fs_ls(const char *dirname) {
- struct ext2fs_node *dirnode;
struct ext2fs_node *dirnode = NULL; int status;
if (dirname == NULL)
@@ -174,7 +174,8 @@ int ext4fs_ls(const char *dirname) FILETYPE_DIRECTORY); if (status != 1) { printf("** Can not find directory. **\n");
ext4fs_free_node(dirnode, &ext4fs_root->diropen);
if (dirnode)ext4fs_free_node(dirnode, &ext4fs_root->diropen);
This looks good. Can you please do a v2 that also updates test/fs/fs-test.sh to have a test for this case? Thanks!
participants (2)
-
Eugen Hristev -
Tom Rini