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grub2
0007-video-readers-png-Abort-sooner-if-a-read-o...
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File 0007-video-readers-png-Abort-sooner-if-a-read-operation-f.patch of Package grub2
From 9db9558e1c75d47beca7ba378a99471c57729be5 Mon Sep 17 00:00:00 2001 From: Daniel Axtens <dja@axtens.net> Date: Tue, 6 Jul 2021 14:02:55 +1000 Subject: [PATCH 07/32] video/readers/png: Abort sooner if a read operation fails Fuzzing revealed some inputs that were taking a long time, potentially forever, because they did not bail quickly upon encountering an I/O error. Try to catch I/O errors sooner and bail out. Signed-off-by: Daniel Axtens <dja@axtens.net> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/video/readers/png.c | 55 ++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 8 deletions(-) diff --git a/grub-core/video/readers/png.c b/grub-core/video/readers/png.c index 54dfedf435..d715c4629f 100644 --- a/grub-core/video/readers/png.c +++ b/grub-core/video/readers/png.c @@ -142,6 +142,7 @@ static grub_uint8_t grub_png_get_byte (struct grub_png_data *data) { grub_uint8_t r; + grub_ssize_t bytes_read = 0; if ((data->inside_idat) && (data->idat_remain == 0)) { @@ -175,7 +176,14 @@ grub_png_get_byte (struct grub_png_data *data) } r = 0; - grub_file_read (data->file, &r, 1); + bytes_read = grub_file_read (data->file, &r, 1); + + if (bytes_read != 1) + { + grub_error (GRUB_ERR_BAD_FILE_TYPE, + "png: unexpected end of data"); + return 0; + } if (data->inside_idat) data->idat_remain--; @@ -231,15 +239,16 @@ grub_png_decode_image_palette (struct grub_png_data *data, if (len == 0) return GRUB_ERR_NONE; - for (i = 0; 3 * i < len && i < 256; i++) + grub_errno = GRUB_ERR_NONE; + for (i = 0; 3 * i < len && i < 256 && grub_errno == GRUB_ERR_NONE; i++) for (j = 0; j < 3; j++) data->palette[i][j] = grub_png_get_byte (data); - for (i *= 3; i < len; i++) + for (i *= 3; i < len && grub_errno == GRUB_ERR_NONE; i++) grub_png_get_byte (data); grub_png_get_dword (data); - return GRUB_ERR_NONE; + return grub_errno; } static grub_err_t @@ -256,9 +265,13 @@ grub_png_decode_image_header (struct grub_png_data *data) return grub_error (GRUB_ERR_BAD_FILE_TYPE, "png: invalid image size"); color_bits = grub_png_get_byte (data); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; data->is_16bit = (color_bits == 16); color_type = grub_png_get_byte (data); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; /* According to PNG spec, no other types are valid. */ if ((color_type & ~(PNG_COLOR_MASK_ALPHA | PNG_COLOR_MASK_COLOR)) @@ -340,14 +353,20 @@ grub_png_decode_image_header (struct grub_png_data *data) if (grub_png_get_byte (data) != PNG_COMPRESSION_BASE) return grub_error (GRUB_ERR_BAD_FILE_TYPE, "png: compression method not supported"); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; if (grub_png_get_byte (data) != PNG_FILTER_TYPE_BASE) return grub_error (GRUB_ERR_BAD_FILE_TYPE, "png: filter method not supported"); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; if (grub_png_get_byte (data) != PNG_INTERLACE_NONE) return grub_error (GRUB_ERR_BAD_FILE_TYPE, "png: interlace method not supported"); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; /* Skip crc checksum. */ grub_png_get_dword (data); @@ -449,7 +468,7 @@ grub_png_get_huff_code (struct grub_png_data *data, struct huff_table *ht) int code, i; code = 0; - for (i = 0; i < ht->max_length; i++) + for (i = 0; i < ht->max_length && grub_errno == GRUB_ERR_NONE; i++) { code = (code << 1) + grub_png_get_bits (data, 1); if (code < ht->maxval[i]) @@ -504,8 +523,14 @@ grub_png_init_dynamic_block (struct grub_png_data *data) grub_uint8_t lens[DEFLATE_HCLEN_MAX]; nl = DEFLATE_HLIT_BASE + grub_png_get_bits (data, 5); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; nd = DEFLATE_HDIST_BASE + grub_png_get_bits (data, 5); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; nb = DEFLATE_HCLEN_BASE + grub_png_get_bits (data, 4); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; if ((nl > DEFLATE_HLIT_MAX) || (nd > DEFLATE_HDIST_MAX) || (nb > DEFLATE_HCLEN_MAX)) @@ -533,7 +558,7 @@ grub_png_init_dynamic_block (struct grub_png_data *data) data->dist_offset); prev = 0; - for (i = 0; i < nl + nd; i++) + for (i = 0; i < nl + nd && grub_errno == GRUB_ERR_NONE; i++) { int n, code; struct huff_table *ht; @@ -721,17 +746,21 @@ grub_png_read_dynamic_block (struct grub_png_data *data) len = cplens[n]; if (cplext[n]) len += grub_png_get_bits (data, cplext[n]); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; n = grub_png_get_huff_code (data, &data->dist_table); dist = cpdist[n]; if (cpdext[n]) dist += grub_png_get_bits (data, cpdext[n]); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; pos = data->wp - dist; if (pos < 0) pos += WSIZE; - while (len > 0) + while (len > 0 && grub_errno == GRUB_ERR_NONE) { data->slide[data->wp] = data->slide[pos]; grub_png_output_byte (data, data->slide[data->wp]); @@ -759,7 +788,11 @@ grub_png_decode_image_data (struct grub_png_data *data) int final; cmf = grub_png_get_byte (data); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; flg = grub_png_get_byte (data); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; if ((cmf & 0xF) != Z_DEFLATED) return grub_error (GRUB_ERR_BAD_FILE_TYPE, @@ -774,7 +807,11 @@ grub_png_decode_image_data (struct grub_png_data *data) int block_type; final = grub_png_get_bits (data, 1); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; block_type = grub_png_get_bits (data, 2); + if (grub_errno != GRUB_ERR_NONE) + return grub_errno; switch (block_type) { @@ -790,7 +827,7 @@ grub_png_decode_image_data (struct grub_png_data *data) grub_png_get_byte (data); grub_png_get_byte (data); - for (i = 0; i < len; i++) + for (i = 0; i < len && grub_errno == GRUB_ERR_NONE; i++) grub_png_output_byte (data, grub_png_get_byte (data)); break; @@ -1045,6 +1082,8 @@ grub_png_decode_png (struct grub_png_data *data) len = grub_png_get_dword (data); type = grub_png_get_dword (data); + if (grub_errno != GRUB_ERR_NONE) + break; data->next_offset = data->file->offset + len + 4; switch (type) -- 2.34.1
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