[PATCH v3 1/2] ntdll: Try mapping free memory region outside of reserved regions.
We assumed that all mapped regions are known by Wine view tree, which is obviously not the case with external allocations. This could lead to memory corruption when find_free_area returns an expected free region which is already mapped. Using MAP_FIXED forces mmap to succeed and corrupts the mapping. This patch uses safe mmap calls to check if the expected free memory is actually free, and iterates over the expected free ranges until it succeeds. Signed-off-by: Rémi Bernon <rbernon(a)codeweavers.com> --- dlls/ntdll/virtual.c | 64 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 53 insertions(+), 11 deletions(-) diff --git a/dlls/ntdll/virtual.c b/dlls/ntdll/virtual.c index 68249de902e..60838c68a55 100644 --- a/dlls/ntdll/virtual.c +++ b/dlls/ntdll/virtual.c @@ -496,6 +496,35 @@ static struct file_view *find_view_range( const void *addr, size_t size ) return NULL; } +/*********************************************************************** + * try_map_free_area + * + * Try mmaping some expected free memory region, eventually stepping and + * retrying inside it, and return where it actually succeeded, or NULL. + */ +static void* try_map_free_area( void *base, void *end, ptrdiff_t step, + void *start, size_t size, int unix_prot ) +{ + void *ptr; + + while (start && base <= start && (char*)start + size <= (char*)end) + { + if ((ptr = wine_anon_mmap( start, size, unix_prot, 0 )) == start) + return start; + TRACE( "Found free area is already mapped, start %p.\n", start ); + + if (ptr != (void *)-1) + munmap( ptr, size ); + + if ((step > 0 && (char *)end - (char *)start < step) || + (step < 0 && (char *)start - (char *)base < -step) || + step == 0) + break; + start = (char *)start + step; + } + + return NULL; +} /*********************************************************************** * find_free_area @@ -503,9 +532,11 @@ static struct file_view *find_view_range( const void *addr, size_t size ) * Find a free area between views inside the specified range. * The csVirtual section must be held by caller. */ -static void *find_free_area( void *base, void *end, size_t size, size_t mask, int top_down ) +static void *find_free_area( void *base, void *end, size_t size, size_t mask, int top_down, + int map_area, int unix_prot ) { struct wine_rb_entry *first = NULL, *ptr = views_tree.root; + ptrdiff_t step = top_down ? -(mask + 1) : (mask + 1); void *start; /* find the first (resp. last) view inside the range */ @@ -538,7 +569,10 @@ static void *find_free_area( void *base, void *end, size_t size, size_t mask, in { struct file_view *view = WINE_RB_ENTRY_VALUE( first, struct file_view, entry ); - if ((char *)view->base + view->size <= (char *)start) break; + if (!map_area && (char *)view->base + view->size <= (char *)start) break; + if (map_area && (start = try_map_free_area( (char *)view->base + view->size, + (char *)start + size, step, + start, size, unix_prot ))) break; start = ROUND_ADDR( (char *)view->base - size, mask ); /* stop if remaining space is not large enough */ if (!start || start >= end || start < base) return NULL; @@ -554,13 +588,17 @@ static void *find_free_area( void *base, void *end, size_t size, size_t mask, in { struct file_view *view = WINE_RB_ENTRY_VALUE( first, struct file_view, entry ); - if ((char *)view->base >= (char *)start + size) break; + if (!map_area && (char *)view->base >= (char *)start + size) break; + if (map_area && (start = try_map_free_area( start, view->base, step, + start, size, unix_prot ))) break; start = ROUND_ADDR( (char *)view->base + view->size + mask, mask ); /* stop if remaining space is not large enough */ if (!start || start >= end || (char *)end - (char *)start < size) return NULL; first = wine_rb_next( first ); } } + + if (!first && map_area) return try_map_free_area( base, end, step, start, size, unix_prot ); return start; } @@ -1054,13 +1092,13 @@ static int alloc_reserved_area_callback( void *start, size_t size, void *arg ) { /* range is split in two by the preloader reservation, try first part */ if ((alloc->result = find_free_area( start, preload_reserve_start, alloc->size, - alloc->mask, alloc->top_down ))) + alloc->mask, alloc->top_down, FALSE, 0 ))) return 1; /* then fall through to try second part */ start = preload_reserve_end; } } - if ((alloc->result = find_free_area( start, end, alloc->size, alloc->mask, alloc->top_down ))) + if ((alloc->result = find_free_area( start, end, alloc->size, alloc->mask, alloc->top_down, FALSE, 0 ))) return 1; return 0; @@ -1148,6 +1186,7 @@ static NTSTATUS map_view( struct file_view **view_ret, void *base, size_t size, { size_t view_size = size + mask + 1; struct alloc_area alloc; + int unix_prot = VIRTUAL_GetUnixProt(vprot); alloc.size = size; alloc.mask = mask; @@ -1158,19 +1197,22 @@ static NTSTATUS map_view( struct file_view **view_ret, void *base, size_t size, { ptr = alloc.result; TRACE( "got mem in reserved area %p-%p\n", ptr, (char *)ptr + size ); - if (wine_anon_mmap( ptr, size, VIRTUAL_GetUnixProt(vprot), MAP_FIXED ) != ptr) + if (wine_anon_mmap( ptr, size, unix_prot, MAP_FIXED ) != ptr) return STATUS_INVALID_PARAMETER; goto done; } - for (;;) + if (zero_bits_64) { - if (!zero_bits_64) - ptr = NULL; - else if (!(ptr = find_free_area( (void*)0, alloc.limit, view_size, mask, top_down ))) + if (!(ptr = find_free_area( (void*)0, alloc.limit, size, mask, top_down, TRUE, unix_prot ))) return STATUS_NO_MEMORY; + TRACE( "got mem with find_free_area %p-%p\n", ptr, (char *)ptr + size ); + goto done; + } - if ((ptr = wine_anon_mmap( ptr, view_size, VIRTUAL_GetUnixProt(vprot), ptr ? MAP_FIXED : 0 )) == (void *)-1) + for (;;) + { + if ((ptr = wine_anon_mmap( NULL, view_size, unix_prot, 0 )) == (void *)-1) { if (errno == ENOMEM) return STATUS_NO_MEMORY; return STATUS_INVALID_PARAMETER; -- 2.24.0.rc2
The search was initiated with base == 0, which returns NULL immediately if MEM_TOP_DOWN is not used. Use address_space_start instead. Signed-off-by: Rémi Bernon <rbernon(a)codeweavers.com> --- dlls/ntdll/virtual.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/dlls/ntdll/virtual.c b/dlls/ntdll/virtual.c index 60838c68a55..80e1c5235fe 100644 --- a/dlls/ntdll/virtual.c +++ b/dlls/ntdll/virtual.c @@ -1204,7 +1204,7 @@ static NTSTATUS map_view( struct file_view **view_ret, void *base, size_t size, if (zero_bits_64) { - if (!(ptr = find_free_area( (void*)0, alloc.limit, size, mask, top_down, TRUE, unix_prot ))) + if (!(ptr = find_free_area( address_space_start, alloc.limit, size, mask, top_down, TRUE, unix_prot ))) return STATUS_NO_MEMORY; TRACE( "got mem with find_free_area %p-%p\n", ptr, (char *)ptr + size ); goto done; -- 2.24.0.rc2
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47974 --- The bug is also about some other issue, but these patches should fix the main crash cause in X Rebirth, as discussed in this bug.
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Rémi Bernon