-- v5: win32u: Avoid leaking previous buffer in get_buffer_space(). win32u: Avoid writing past allocated memory in peek_message().
From: Paul Gofman pgofman@codeweavers.com
--- dlls/win32u/message.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-)
diff --git a/dlls/win32u/message.c b/dlls/win32u/message.c index 2b416f39241..3a17c4689ff 100644 --- a/dlls/win32u/message.c +++ b/dlls/win32u/message.c @@ -469,9 +469,13 @@ static inline void push_string( struct packed_message *data, LPCWSTR str ) }
/* make sure that there is space for 'size' bytes in buffer, growing it if needed */ -static inline void *get_buffer_space( void **buffer, size_t size, size_t prev_size ) +static inline void *get_buffer_space( void **buffer, size_t size, size_t *buffer_size ) { - if (prev_size < size) *buffer = malloc( size ); + if (*buffer_size < size) + { + *buffer = malloc( size ); + *buffer_size = size; + } return *buffer; }
@@ -522,7 +526,7 @@ BOOL set_keyboard_auto_repeat( BOOL enable ) * Unpack a message received from another process. */ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lparam, - void **buffer, size_t size ) + void **buffer, size_t size, size_t *buffer_size ) { size_t minsize = 0; union packed_structs *ps = *buffer; @@ -585,7 +589,7 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa break; case WM_GETTEXT: case WM_ASKCBFORMATNAME: - if (!get_buffer_space( buffer, (*wparam * sizeof(WCHAR)), size )) return FALSE; + if (!get_buffer_space( buffer, (*wparam * sizeof(WCHAR)), buffer_size )) return FALSE; break; case WM_WININICHANGE: if (!*lparam) return TRUE; @@ -726,17 +730,17 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa minsize = sizeof(SCROLLINFO); break; case SBM_GETSCROLLINFO: - if (!get_buffer_space( buffer, sizeof(SCROLLINFO), size )) return FALSE; + if (!get_buffer_space( buffer, sizeof(SCROLLINFO), buffer_size )) return FALSE; break; case SBM_GETSCROLLBARINFO: - if (!get_buffer_space( buffer, sizeof(SCROLLBARINFO), size )) return FALSE; + if (!get_buffer_space( buffer, sizeof(SCROLLBARINFO), buffer_size )) return FALSE; break; case EM_GETSEL: case SBM_GETRANGE: case CB_GETEDITSEL: if (*wparam || *lparam) { - if (!get_buffer_space( buffer, 2 * sizeof(DWORD), size )) return FALSE; + if (!get_buffer_space( buffer, 2 * sizeof(DWORD), buffer_size )) return FALSE; if (*wparam) *wparam = (WPARAM)*buffer; if (*lparam) *lparam = (LPARAM)((DWORD *)*buffer + 1); } @@ -744,7 +748,7 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa case EM_GETRECT: case LB_GETITEMRECT: case CB_GETDROPPEDCONTROLRECT: - if (!get_buffer_space( buffer, sizeof(RECT), size )) return FALSE; + if (!get_buffer_space( buffer, sizeof(RECT), buffer_size )) return FALSE; break; case EM_SETRECT: case EM_SETRECTNP: @@ -755,7 +759,7 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa WORD *len_ptr, len; if (size < sizeof(WORD)) return FALSE; len = *(WORD *)*buffer; - if (!get_buffer_space( buffer, (len + 1) * sizeof(WCHAR), size )) return FALSE; + if (!get_buffer_space( buffer, (len + 1) * sizeof(WCHAR), buffer_size )) return FALSE; len_ptr = *buffer; len_ptr[0] = len_ptr[1] = len; *lparam = (LPARAM)(len_ptr + 1); @@ -780,26 +784,24 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa break; case CB_GETLBTEXT: { - size_t prev_size = size; if (combobox_has_strings( hwnd )) size = (send_message( hwnd, CB_GETLBTEXTLEN, *wparam, 0 ) + 1) * sizeof(WCHAR); else size = sizeof(ULONG_PTR); - if (!get_buffer_space( buffer, size, prev_size )) return FALSE; + if (!get_buffer_space( buffer, size, buffer_size )) return FALSE; break; } case LB_GETTEXT: { - size_t prev_size = size; if (listbox_has_strings( hwnd )) size = (send_message( hwnd, LB_GETTEXTLEN, *wparam, 0 ) + 1) * sizeof(WCHAR); else size = sizeof(ULONG_PTR); - if (!get_buffer_space( buffer, size, prev_size )) return FALSE; + if (!get_buffer_space( buffer, size, buffer_size )) return FALSE; break; } case LB_GETSELITEMS: - if (!get_buffer_space( buffer, *wparam * sizeof(UINT), size )) return FALSE; + if (!get_buffer_space( buffer, *wparam * sizeof(UINT), buffer_size )) return FALSE; break; case WM_NEXTMENU: { @@ -814,7 +816,7 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa case WM_SIZING: case WM_MOVING: minsize = sizeof(RECT); - if (!get_buffer_space( buffer, sizeof(RECT), size )) return FALSE; + if (!get_buffer_space( buffer, sizeof(RECT), buffer_size )) return FALSE; break; case WM_MDICREATE: { @@ -880,7 +882,7 @@ static BOOL unpack_message( HWND hwnd, UINT message, WPARAM *wparam, LPARAM *lpa } case WM_MDIGETACTIVE: if (!*lparam) return TRUE; - if (!get_buffer_space( buffer, sizeof(BOOL), size )) return FALSE; + if (!get_buffer_space( buffer, sizeof(BOOL), buffer_size )) return FALSE; break; case WM_DEVICECHANGE: if (!(*wparam & 0x8000)) return TRUE; @@ -2788,7 +2790,7 @@ int peek_message( MSG *msg, const struct peek_message_filter *filter ) case MSG_NOTIFY: info.flags = ISMEX_NOTIFY; if (!unpack_message( info.msg.hwnd, info.msg.message, &info.msg.wParam, - &info.msg.lParam, &buffer, size )) + &info.msg.lParam, &buffer, size, &buffer_size )) continue; break; case MSG_CALLBACK: @@ -2866,7 +2868,7 @@ int peek_message( MSG *msg, const struct peek_message_filter *filter ) case MSG_OTHER_PROCESS: info.flags = ISMEX_SEND; if (!unpack_message( info.msg.hwnd, info.msg.message, &info.msg.wParam, - &info.msg.lParam, &buffer, size )) + &info.msg.lParam, &buffer, size, &buffer_size )) { /* ignore it */ reply_message( &info, 0, &info.msg );
From: Paul Gofman pgofman@codeweavers.com
--- dlls/win32u/message.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/dlls/win32u/message.c b/dlls/win32u/message.c index 3a17c4689ff..8f12acfd6d1 100644 --- a/dlls/win32u/message.c +++ b/dlls/win32u/message.c @@ -473,7 +473,14 @@ static inline void *get_buffer_space( void **buffer, size_t size, size_t *buffer { if (*buffer_size < size) { - *buffer = malloc( size ); + void *new; + + if (!(new = realloc( *buffer, size ))) + { + ERR( "Failed to allocate %zu bytes.\n", size ); + return NULL; + } + *buffer = new; *buffer_size = size; } return *buffer;
v4:
* handle realloc() error; * rename prev_size -> buffer_size.
This merge request was approved by Jacek Caban.
On Tue Mar 26 15:17:58 2024 +0000, Paul Gofman wrote:
Do we always reallocate to larger size? It is currently reallocated based on the actual message size returned by the server, while buffer_size in peek_message may be bigger (and it is first allocated to 1024 bytes). Granted, I only reproduced the actual memory corruption with Proton, but it seems to me that in this regard the handling is the same.
Right, I see, thanks. It's possible in cases where we don't actually need any realloc.
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Jacek Caban (＠jacek) -
Paul Gofman
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Paul Gofman (＠gofman)