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[edk2-platforms][PATCH v3 11/11] Ext4Pkg: Filter out directory entry names containing \0 as invalid
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The directory entry name conventions forbid having null-terminator
symbols in its body and can lead to undefined behavior conditions and crashes Cc: Marvin Häuser <mhaeuser@...> Cc: Pedro Falcato <pedro.falcato@...> Cc: Vitaly Cheptsov <vit9696@...> Fixes: 89b2bb0db263 ("Ext4Pkg: Fix and clarify handling regarding non-utf8 dir entries") Signed-off-by: Savva Mitrofanov <savvamtr@...> --- Features/Ext4Pkg/Ext4Dxe/Directory.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/Features/Ext4Pkg/Ext4Dxe/Directory.c b/Features/Ext4Pkg/Ext4Dxe/Directory.c index 0753a20b5377..465749c9b51d 100644 --- a/Features/Ext4Pkg/Ext4Dxe/Directory.c +++ b/Features/Ext4Pkg/Ext4Dxe/Directory.c @@ -28,9 +28,16 @@ Ext4GetUcs2DirentName ( { CHAR8 Utf8NameBuf[EXT4_NAME_MAX + 1]; UINT16 *Str; + UINTN Index; EFI_STATUS Status; - CopyMem (Utf8NameBuf, Entry->name, Entry->name_len); + for (Index = 0; Index < Entry->name_len; ++Index) { + if (Entry->name[Index] == '\0') { + return EFI_INVALID_PARAMETER; + } + + Utf8NameBuf[Index] = Entry->name[Index]; + } Utf8NameBuf[Entry->name_len] = '\0'; -- 2.39.0 |
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Marvin Häuser
On 27. Jan 2023, at 10:29, Savva Mitrofanov <savvamtr@...> wrote:
I *really* do not like UINTN in code that does not deal with buffer addresses and sizes. I'd change it to UINT8, but I'll leave it up to Pedro. EFI_STATUS Status; |
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Pedro Falcato
On Fri, Jan 27, 2023 at 10:04 AM Marvin Häuser <mhaeuser@...> wrote:
Considering this is a size (length of name) and it gets explicitly bounded by name_len (a UINT8) I'm okay with it. But if for some reason you need to submit a v4, please change. Reviewed-by: Pedro Falcato <pedro.falcato@...> -- Pedro |
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Marvin Häuser
On 27. Jan 2023, at 15:09, Pedro Falcato <pedro.falcato@...> wrote:Well, being a "size" is not sufficient, I explicitly referred to buffer sizes. Say, you get an arbitrarily long buffer from a caller, its size parameter should probably be UINTN, to be able to optimally leverage the platform memory and be flexible. This is not a buffer size, this is a bounded index of an architecture-agnostic data structure. I simply do not want behaviour that depends on the host architecture in architecture-agnostic code for no reason. We actually had multiple prior examples of bugs due to this, though this is obviously fine (thus not demanding it's changed). bounded by name_len (a UINT8) I'm okay with it. But if for some reason |
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It is not so important from my point of view, however, I corrected this in the referenced repository fork.
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On 27 Jan 2023, at 16:04, Marvin Häuser <mhaeuser@...> wrote: |
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Marvin Häuser
As Pedro agreed, forgot to add
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Reviewed-by: Marvin Häuser <mhaeuser@...> @Pedro feel free to change to UINT8 on push nevertheless. :) On 27. Jan 2023, at 15:14, Marvin Häuser <mhaeuser@...> wrote: |
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