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[209.51.188.17]) by mx.google.com with ESMTPS id g22si5325503vsf.372.2021.11.11.03.06.34 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 11 Nov 2021 03:06:35 -0800 (PST) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org" Received: from localhost ([::1]:51686 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ml7uc-0002WQ-Ef for patch@linaro.org; Thu, 11 Nov 2021 06:06:34 -0500 Received: from eggs.gnu.org ([209.51.188.92]:50790) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ml7tN-0002UE-KD for qemu-devel@nongnu.org; Thu, 11 Nov 2021 06:05:17 -0500 Received: from mout.kundenserver.de ([212.227.126.133]:47505) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ml7tL-0001NC-Aw for qemu-devel@nongnu.org; Thu, 11 Nov 2021 06:05:17 -0500 Received: from quad ([82.142.28.210]) by mrelayeu.kundenserver.de (mreue010 [212.227.15.167]) with ESMTPSA (Nemesis) id 1MwwuJ-1mWK4B2K6d-00ySVn; Thu, 11 Nov 2021 12:05:13 +0100 From: Laurent Vivier To: qemu-devel@nongnu.org Subject: [PULL 4/4] linux-user: Rewrite do_getdents, do_getdents64 Date: Thu, 11 Nov 2021 12:05:04 +0100 Message-Id: <20211111110504.1574242-5-laurent@vivier.eu> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211111110504.1574242-1-laurent@vivier.eu> References: <20211111110504.1574242-1-laurent@vivier.eu> MIME-Version: 1.0 X-Provags-ID: V03:K1:TrBN8cvwb47goh6sHFTlUqiwrGspctKFmIUoUl1kuFEYWshXjzN PeSHNpUu1tjArmbbrxb7xcAQrWuhxcp5JR4vUmNw/r4xSqe9JreosX84Sf8MHbs20RKF+3W VrfO1rCiYMD0csxQVCgyyVugndDpDBHbS/CHe9Nr3Yzsznx2yfkLXUWEF+e0R9jCZQW84vs Idhe/OslXAz2z1aw6k5RA== X-UI-Out-Filterresults: notjunk:1;V03:K0:KSW34BrYp7U=:YYPwYIYcoD4oOXjaN3PA+u 7tFFKxRYqU8zDo5sWQXLWWL5iMY9AFRKxVTyDCCKPWQpShgoJfyoR5MLNspsA2td86UcrFovH lCV3IFer0EnfTJQzmfJMBRW1KHgA347e0VmciiI8S/dVm6qj51JhCba8AxNbI7DyFrAfg+SES hK7kOKr0DEM/z29zZhPP1Zssu53Veb2ozw8hHjzx/OcOoGnims1TMPXLsQOMnAE9grvdVRF38 FdFV1OMTn13YAk6aBn1qFwWqb3yrGgq8KVoGpr2P3rHqFUxpapfqgpZDip6TmLaafRNA1UpCU vpwdtnVusnpCh5VPJ7/ggTyZThCjnaGUrX4XL4oPVnavRg6VHMRKv9P4IhGOD5ov4tAnip1Gf 1HbTxWPSUA4O0X03rb//v+F6KeCglqEal6EPBBEE7CC1+7SmLvhSfI0vcZ4Qus3FdvE+t3SLr RIeCAfIoMYd2AKXto+MACtH2BVwr9HpGd+ymSkCUX8mfpuiDFFCOQ8IPauJuyiQ+I+y8DAC8/ OyLmtmvIRMFhUqH+ViNfHHk1cdplDxDOWRAndrEPUuNd9J7zi2+WhUjJ+lLvYLflyBweC7fcX Hl69xFf3ZV/MQoonJb0w8bjmTXcDhwrHf2hxtsyI4R5zDU9WQe88nGnsONoyIWMny4iWvYQU9 PS/6G73yoBDqPiOLydm+uRuNKrgz+2ivOja8bQhyQ+yEwBhe9tVhDPnhYkwchXUYnPjE= Received-SPF: none client-ip=212.227.126.133; envelope-from=laurent@vivier.eu; helo=mout.kundenserver.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Richard Henderson , Laurent Vivier Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" From: Richard Henderson Always allocate host storage; this ensures that the struct is sufficiently aligned for the host. Merge the three host implementations of getdents via a few ifdefs. Utilize the same method for do_getdents64. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/704 Signed-off-by: Richard Henderson Message-Id: <20211107124845.1174791-5-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier --- linux-user/syscall.c | 243 ++++++++++++++++++------------------------- 1 file changed, 101 insertions(+), 142 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 499415ad81b8..01efd5773b9a 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8140,172 +8140,131 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask, } #ifdef TARGET_NR_getdents -static int do_getdents(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents(abi_long arg1, abi_long arg2, abi_long count) { - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; + + hdirp = g_try_malloc(count); + if (!hdirp) { + return -TARGET_ENOMEM; + } #ifdef EMULATE_GETDENTS_WITH_GETDENTS -# if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64 - struct target_dirent *target_dirp; - struct linux_dirent *dirp; - abi_long count = arg3; + hlen = sys_getdents(arg1, hdirp, count); +#else + hlen = sys_getdents64(arg1, hdirp, count); +#endif - dirp = g_try_malloc(count); - if (!dirp) { - return -TARGET_ENOMEM; + hlen = get_errno(hlen); + if (is_error(hlen)) { + return hlen; } - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - struct target_dirent *tde; - int len = ret; - int reclen, treclen; - int count1, tnamelen; - - count1 = 0; - de = dirp; - target_dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!target_dirp) { - return -TARGET_EFAULT; - } - tde = target_dirp; - while (len > 0) { - reclen = de->d_reclen; - tnamelen = reclen - offsetof(struct linux_dirent, d_name); - assert(tnamelen >= 0); - treclen = tnamelen + offsetof(struct target_dirent, d_name); - assert(count1 + treclen <= count); - tde->d_reclen = tswap16(treclen); - tde->d_ino = tswapal(de->d_ino); - tde->d_off = tswapal(de->d_off); - memcpy(tde->d_name, de->d_name, tnamelen); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - tde = (struct target_dirent *)((char *)tde + treclen); - count1 += treclen; - } - ret = count1; - unlock_user(target_dirp, arg2, ret); - } - g_free(dirp); -# else - struct linux_dirent *dirp; - abi_long count = arg3; - - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { return -TARGET_EFAULT; } - ret = get_errno(sys_getdents(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) { - break; - } - de->d_reclen = tswap16(reclen); - tswapls(&de->d_ino); - tswapls(&de->d_off); - de = (struct linux_dirent *)((char *)de + reclen); - len -= reclen; - } - } - unlock_user(dirp, arg2, ret); -# endif + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + struct linux_dirent *hde = hdirp + hoff; #else - /* Implement getdents in terms of getdents64 */ - struct linux_dirent64 *dirp; - abi_long count = arg3; + struct linux_dirent64 *hde = hdirp + hoff; +#endif + struct target_dirent *tde = tdirp + toff; + int namelen; + uint8_t type; - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { - return -TARGET_EFAULT; - } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { /* - * Convert the dirent64 structs to target dirent. We do this - * in-place, since we can guarantee that a target_dirent is no - * larger than a dirent64; however this means we have to be - * careful to read everything before writing in the new format. + * If somehow the host dirent is smaller than the target dirent, + * then the host could return more dirent in the buffer than we + * can pass on to the host. This could be fixed by returning + * fewer dirent to the guest and lseek on the dirfd to reset the + * file pointer to the final hde->d_off. */ - struct linux_dirent64 *de; - struct target_dirent *tde; - int len = ret; - int tlen = 0; + QEMU_BUILD_BUG_ON(sizeof(*hde) < sizeof(*tde)); - de = dirp; - tde = (struct target_dirent *)dirp; - while (len > 0) { - int namelen, treclen; - int reclen = de->d_reclen; - uint64_t ino = de->d_ino; - int64_t off = de->d_off; - uint8_t type = de->d_type; - - namelen = strlen(de->d_name); - treclen = offsetof(struct target_dirent, d_name) + namelen + 2; - treclen = QEMU_ALIGN_UP(treclen, sizeof(abi_long)); - - memmove(tde->d_name, de->d_name, namelen + 1); - tde->d_ino = tswapal(ino); - tde->d_off = tswapal(off); - tde->d_reclen = tswap16(treclen); - /* - * The target_dirent type is in what was formerly a padding - * byte at the end of the structure: - */ - *(((char *)tde) + treclen - 1) = type; + namelen = strlen(hde->d_name); + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent, d_name) + namelen + 2; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent)); - de = (struct linux_dirent64 *)((char *)de + reclen); - tde = (struct target_dirent *)((char *)tde + treclen); - len -= reclen; - tlen += treclen; - } - ret = tlen; - } - unlock_user(dirp, arg2, ret); + tde->d_ino = tswapal(hde->d_ino); + tde->d_off = tswapal(hde->d_off); + tde->d_reclen = tswap16(treclen); + memcpy(tde->d_name, hde->d_name, namelen + 1); + + /* + * The getdents type is in what was formerly a padding byte at the + * end of the structure. + */ +#ifdef EMULATE_GETDENTS_WITH_GETDENTS + type = *((uint8_t *)hde + hreclen - 1); +#else + type = hde->d_type; #endif - return ret; + *((uint8_t *)tde + treclen - 1) = type; + } + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents */ #if defined(TARGET_NR_getdents64) && defined(__NR_getdents64) -static int do_getdents64(abi_long arg1, abi_long arg2, abi_long arg3) +static int do_getdents64(abi_long arg1, abi_long arg2, abi_long count) { - struct linux_dirent64 *dirp; - abi_long count = arg3; - int ret; + g_autofree void *hdirp = NULL; + void *tdirp; + int hlen, hoff, toff; + int hreclen, treclen; + + hdirp = g_try_malloc(count); + if (!hdirp) { + return -TARGET_ENOMEM; + } + + hlen = get_errno(sys_getdents64(arg1, hdirp, count)); + if (is_error(hlen)) { + return hlen; + } - dirp = lock_user(VERIFY_WRITE, arg2, count, 0); - if (!dirp) { + tdirp = lock_user(VERIFY_WRITE, arg2, count, 0); + if (!tdirp) { return -TARGET_EFAULT; } - ret = get_errno(sys_getdents64(arg1, dirp, count)); - if (!is_error(ret)) { - struct linux_dirent64 *de; - int len = ret; - int reclen; - de = dirp; - while (len > 0) { - reclen = de->d_reclen; - if (reclen > len) { - break; - } - de->d_reclen = tswap16(reclen); - tswap64s((uint64_t *)&de->d_ino); - tswap64s((uint64_t *)&de->d_off); - de = (struct linux_dirent64 *)((char *)de + reclen); - len -= reclen; - } + + for (hoff = toff = 0; hoff < hlen; hoff += hreclen, toff += treclen) { + struct linux_dirent64 *hde = hdirp + hoff; + struct target_dirent64 *tde = tdirp + toff; + int namelen; + + /* + * If somehow the host dirent is smaller than the target dirent, + * then the host could return more dirent in the buffer than we + * can pass on to the host. This could be fixed by returning + * fewer dirent to the guest and lseek on the dirfd to reset the + * file pointer to the final hde->d_off. + */ + QEMU_BUILD_BUG_ON(sizeof(*hde) < sizeof(*tde)); + + namelen = strlen(hde->d_name) + 1; + hreclen = hde->d_reclen; + treclen = offsetof(struct target_dirent64, d_name) + namelen; + treclen = QEMU_ALIGN_UP(treclen, __alignof(struct target_dirent64)); + + tde->d_ino = tswap64(hde->d_ino); + tde->d_off = tswap64(hde->d_off); + tde->d_reclen = tswap16(treclen); + tde->d_type = hde->d_type; + memcpy(tde->d_name, hde->d_name, namelen); } - unlock_user(dirp, arg2, ret); - return ret; + + unlock_user(tdirp, arg2, toff); + return toff; } #endif /* TARGET_NR_getdents64 */